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2. Data publication with the structural biology data grid supports live analysis.

Author

Meyer, Peter A, Socias, Stephanie, Key, Jason, Ransey, Elizabeth, Tjon, Emily C, Buschiazzo, Alejandro, Lei, Ming, Botka, Chris, Withrow, James, Neau, David, Rajashankar, Kanagalaghatta, Anderson, Karen S, Baxter, Richard H, Blacklow, Stephen C, Boggon, Titus J, Bonvin, Alexandre MJJ, Borek, Dominika, Brett, Tom J, Caflisch, Amedeo, Chang, Chung-I, Chazin, Walter J, Corbett, Kevin D, Cosgrove, Michael S, Crosson, Sean, Dhe-Paganon, Sirano, Di Cera, Enrico, Drennan, Catherine L, Eck, Michael J, Eichman, Brandt F, Fan, Qing R, Ferré-D'Amaré, Adrian R, Fromme, J Christopher, Garcia, K Christopher, Gaudet, Rachelle, Gong, Peng, Harrison, Stephen C, Heldwein, Ekaterina E, Jia, Zongchao, Keenan, Robert J, Kruse, Andrew C, Kvansakul, Marc, McLellan, Jason S, Modis, Yorgo, Nam, Yunsun, Otwinowski, Zbyszek, Pai, Emil F, Pereira, Pedro José Barbosa, Petosa, Carlo, Raman, CS, Rapoport, Tom A, Roll-Mecak, Antonina, Rosen, Michael K, Rudenko, Gabby, Schlessinger, Joseph, Schwartz, Thomas U, Shamoo, Yousif, Sondermann, Holger, Tao, Yizhi J, Tolia, Niraj H, Tsodikov, Oleg V, Westover, Kenneth D, Wu, Hao, Foster, Ian, Fraser, James S, Maia, Filipe RNC, Gonen, Tamir, Kirchhausen, Tom, Diederichs, Kay, Crosas, Mercè, and Sliz, Piotr

Subjects
Macromolecular Substances, Crystallography, X-Ray, Publications, Internet, Software, Databases, Genetic, Networking and Information Technology R&D, 1.5 Resources and infrastructure (underpinning)
Abstract

Access to experimental X-ray diffraction image data is fundamental for validation and reproduction of macromolecular models and indispensable for development of structural biology processing methods. Here, we established a diffraction data publication and dissemination system, Structural Biology Data Grid (SBDG; data.sbgrid.org), to preserve primary experimental data sets that support scientific publications. Data sets are accessible to researchers through a community driven data grid, which facilitates global data access. Our analysis of a pilot collection of crystallographic data sets demonstrates that the information archived by SBDG is sufficient to reprocess data to statistics that meet or exceed the quality of the original published structures. SBDG has extended its services to the entire community and is used to develop support for other types of biomedical data sets. It is anticipated that access to the experimental data sets will enhance the paradigm shift in the community towards a much more dynamic body of continuously improving data analysis.

Published
2016

6. Time-resolved crystallographic studies of the heme domain of the oxygen sensor FixL: Structural dynamics of ligand rebinding and their relation to signal transduction

Author

Key, Jason, Srajer, Vukica, Pahl, Reinhard, and Moffat, Keith

Subjects
Carbon monoxide -- Structure, Carbon monoxide -- Properties, Transduction -- Research, Ligand binding (Biochemistry) -- Research, Biological sciences, Chemistry
Abstract

Time-resolved Laue diffraction studies of CO recombination in Bradyrhizobium japonicum (bj) bjFixLH was conducted to investigate the molecular basis for enzymatic activity dependence and the dynamics associated with conversion between ligated and unligated states. The results show that structural relaxation from the CO-bound to the deoxy form of bjFixLH is rapid and is complete within 1 [mu]s despite the fact that overall CO recombination in bjFixLH is approximately 100-fold slower than sperm whale myoglobin.

Published
2007

7. Structure of the redox sensor domain of Azotobacter vinelandii NifL at atomic resolution: Signaling, dimerization and mechanism

Author

Key, Jason, Hefti, Marco, Purcell, Erin B., and Moffat, Keith

Subjects
Oxidation-reduction reaction -- Observations, Crystals -- Structure, Crystals -- Research, Biological sciences, Chemistry
Abstract

The crystal structure of the redox sensor domain of Azotobacter vinelandii NifL (AvNifLF) at 1.04 A resolution is determined to explore the mechanism of redox state recognition and signal transduction within the class of flavin-based sensor proteins. It is revealed that there are distinct structural differences between the FAD-based AvNifLF domain and related FMN-based photosensor proteins.

Published
2007

9. Crystal structures of deoxy and CO-bound bjFixLH reveal details of ligand recognition and signaling

Author

Key, Jason and Moffat, Keith

Subjects
Rhizobium -- Genetic aspects, Rhizobium -- Research, Hydrogen -- Research, Carbon dioxide -- Structure, Carbon dioxide -- Research, Biological sciences, Chemistry
Abstract

The structures of CO-bound bjFixLH in R32 and C2 crystal forms using F(sub o)(deoxy)-F(sub o)(CO) difference maps to elucidate the small structural changes associated with binding of CO were examined to investigate the mechanism of kinase inhibition by weak ligands. These maps showed a shift of the residues of the H(sub alpha) and I(sub beta) strands upon CO binding, driven by the steric interaction between the ligand and the side chain of Leu236.

Published
2005

17. Principles of ligand binding within a completely buried cavity in HIF2[alpha] PAS-

Author

Key, Jason, Scheuermann, Thomas H., Anderson, Peter C., Daggett, Valerie, and Gardner, Kevin H.

Subjects
Ligand binding (Biochemistry) -- Analysis, Nuclear magnetic resonance spectroscopy -- Usage, Solvation -- Analysis, Transition state (Chemistry) -- Analysis, X-ray crystallography -- Usage, Chemistry
Abstract

Several techniques are simultaneously employed to explain the structures and equilibrium of the hypoxia-inducible factor, HIF2[alpha] PAS-B with different artificial ligands. The various phenomenon involved in the binding of ligands in these factors are also explained.

Published
2009

18. Dynamics of carbon monoxide photodissociation in bradyrhizobium japonicum fixl probed by picosecond midinfrared spectroscopy

Author

Wilderen, Luuk J. G. W. van, Key, Jason M., Stokkum, Ivo H. M. Van, Grondelle, Rienk van, and Groot, Marie Louise

Subjects
Binding proteins -- Structure, Binding proteins -- Physiological aspects, Binding proteins -- Research, Carbon monoxide -- Research, Infrared spectroscopy -- Usage, Photolysis -- Research, Chemicals, plastics and rubber industries
Published
2009

19. SBGrid Databank

Author

Meyer, Peter A., primary, Key, Jason, additional, Crosas, Mercè, additional, and Sliz, Piotr, additional

Published
2017
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20. Data publication with the structural biology data grid supports live analysis

Author

Massachusetts Institute of Technology. Department of Biology, Massachusetts Institute of Technology. Department of Chemistry, Drennan, Catherine L., Schwartz, Thomas, Meyer, Peter A., Socias, Stephanie, Key, Jason, Ransey, Elizabeth, Tjon, Emily C., Buschiazzo, Alejandro, Lei, Ming, Botka, Chris, Withrow, James, Neau, David, Rajashankar, Kanagalaghatta, Anderson, Karen S., Baxter, Richard H., Blacklow, Stephen C., Boggon, Titus J., Bonvin, Alexandre M. J. J., Borek, Dominika, Brett, Tom J., Caflisch, Amedeo, Chang, Chung-I, Chazin, Walter J., Corbett, Kevin D., Cosgrove, Michael S., Crosson, Sean, Dhe-Paganon, Sirano, Di Cera, Enrico, Eck, Michael J., Eichman, Brandt F., Fan, Qing R., Ferré-D'Amaré, Adrian R., Fromme, J. Christopher, Garcia, K. Christopher, Gaudet, Rachelle, Gong, Peng, Harrison, Stephen C., Heldwein, Ekaterina E., Jia, Zongchao, Keenan, Robert J., Kruse, Andrew C., Kvansakul, Marc, McLellan, Jason S., Modis, Yorgo, Nam, Yunsun, Otwinowski, Zbyszek, Pai, Emil F., Pereira, Pedro José Barbosa, Petosa, Carlo, Raman, C. S., Rapoport, Tom A., Roll-Mecak, Antonina, Rosen, Michael K., Rudenko, Gabby, Schlessinger, Joseph, Shamoo, Yousif, Sondermann, Holger, Tao, Yizhi J., Tolia, Niraj H., Tsodikov, Oleg V., Westover, Kenneth D., Wu, Hao, Foster, Ian, Fraser, James S., Maia, Filipe R. N C., Gonen, Tamir, Kirchhausen, Tom, Diederichs, Kay, Crosas, Mercè, Sliz, Piotr, Massachusetts Institute of Technology. Department of Biology, Massachusetts Institute of Technology. Department of Chemistry, Drennan, Catherine L., Schwartz, Thomas, Meyer, Peter A., Socias, Stephanie, Key, Jason, Ransey, Elizabeth, Tjon, Emily C., Buschiazzo, Alejandro, Lei, Ming, Botka, Chris, Withrow, James, Neau, David, Rajashankar, Kanagalaghatta, Anderson, Karen S., Baxter, Richard H., Blacklow, Stephen C., Boggon, Titus J., Bonvin, Alexandre M. J. J., Borek, Dominika, Brett, Tom J., Caflisch, Amedeo, Chang, Chung-I, Chazin, Walter J., Corbett, Kevin D., Cosgrove, Michael S., Crosson, Sean, Dhe-Paganon, Sirano, Di Cera, Enrico, Eck, Michael J., Eichman, Brandt F., Fan, Qing R., Ferré-D'Amaré, Adrian R., Fromme, J. Christopher, Garcia, K. Christopher, Gaudet, Rachelle, Gong, Peng, Harrison, Stephen C., Heldwein, Ekaterina E., Jia, Zongchao, Keenan, Robert J., Kruse, Andrew C., Kvansakul, Marc, McLellan, Jason S., Modis, Yorgo, Nam, Yunsun, Otwinowski, Zbyszek, Pai, Emil F., Pereira, Pedro José Barbosa, Petosa, Carlo, Raman, C. S., Rapoport, Tom A., Roll-Mecak, Antonina, Rosen, Michael K., Rudenko, Gabby, Schlessinger, Joseph, Shamoo, Yousif, Sondermann, Holger, Tao, Yizhi J., Tolia, Niraj H., Tsodikov, Oleg V., Westover, Kenneth D., Wu, Hao, Foster, Ian, Fraser, James S., Maia, Filipe R. N C., Gonen, Tamir, Kirchhausen, Tom, Diederichs, Kay, Crosas, Mercè, and Sliz, Piotr

Abstract

Access to experimental X-ray diffraction image data is fundamental for validation and reproduction of macromolecular models and indispensable for development of structural biology processing methods. Here, we established a diffraction data publication and dissemination system, Structural Biology Data Grid (SBDG; data.sbgrid.org), to preserve primary experimental data sets that support scientific publications. Data sets are accessible to researchers through a community driven data grid, which facilitates global data access. Our analysis of a pilot collection of crystallographic data sets demonstrates that the information archived by SBDG is sufficient to reprocess data to statistics that meet or exceed the quality of the original published structures. SBDG has extended its services to the entire community and is used to develop support for other types of biomedical data sets. It is anticipated that access to the experimental data sets will enhance the paradigm shift in the community towards a much more dynamic body of continuously improving data analysis.

Published
2017

21. Data publication with the structural biology data grid supports live analysis

Author

Meyer, Peter A., Socias, Stephanie, Key, Jason, Ransey, Elizabeth, Tjon, Emily C., Buschiazzo, Alejandro, Lei, Ming, Botka, Chris, Withrow, James, Neau, David, Rajashankar, Kanagalaghatta, Anderson, Karen S., Baxter, Richard H., Blacklow, Stephen C., Boggon, Titus J., Bonvin, Alexandre M J J, Borek, Dominika, Brett, Tom J., Caflisch, Amedeo, Chang, Chung I., Chazin, Walter J., Corbett, Kevin D., Cosgrove, Michael S., Crosson, Sean, Dhe-Paganon, Sirano, Di Cera, Enrico, Drennan, Catherine L., Eck, Michael J., Eichman, Brandt F., Fan, Qing R., Ferré-D'Amaré, Adrian R., Fromme, J. Christopher, Garcia, K. Christopher, Gaudet, Rachelle, Gong, Peng, Harrison, Stephen C., Heldwein, Ekaterina E., Jia, Zongchao, Keenan, Robert J., Kruse, Andrew C., Kvansakul, Marc, McLellan, Jason S., Modis, Yorgo, Nam, Yunsun, Otwinowski, Zbyszek, Pai, Emil F., Pereira, Pedro José Barbosa, Petosa, Carlo, Raman, C. S., Rapoport, Tom A., Roll-Mecak, Antonina, Rosen, Michael K., Rudenko, Gabby, Schlessinger, Joseph, Schwartz, Thomas U., Shamoo, Yousif, Sondermann, Holger, Tao, Yizhi J., Tolia, Niraj H., Tsodikov, Oleg V., Westover, Kenneth D., Wu, Hao, Foster, Ian, Fraser, James S., Maia, Filipe R N C, Gonen, Tamir, Kirchhausen, Tom, Diederichs, Kay, Crosas, Mercé, Sliz, Piotr, Meyer, Peter A., Socias, Stephanie, Key, Jason, Ransey, Elizabeth, Tjon, Emily C., Buschiazzo, Alejandro, Lei, Ming, Botka, Chris, Withrow, James, Neau, David, Rajashankar, Kanagalaghatta, Anderson, Karen S., Baxter, Richard H., Blacklow, Stephen C., Boggon, Titus J., Bonvin, Alexandre M J J, Borek, Dominika, Brett, Tom J., Caflisch, Amedeo, Chang, Chung I., Chazin, Walter J., Corbett, Kevin D., Cosgrove, Michael S., Crosson, Sean, Dhe-Paganon, Sirano, Di Cera, Enrico, Drennan, Catherine L., Eck, Michael J., Eichman, Brandt F., Fan, Qing R., Ferré-D'Amaré, Adrian R., Fromme, J. Christopher, Garcia, K. Christopher, Gaudet, Rachelle, Gong, Peng, Harrison, Stephen C., Heldwein, Ekaterina E., Jia, Zongchao, Keenan, Robert J., Kruse, Andrew C., Kvansakul, Marc, McLellan, Jason S., Modis, Yorgo, Nam, Yunsun, Otwinowski, Zbyszek, Pai, Emil F., Pereira, Pedro José Barbosa, Petosa, Carlo, Raman, C. S., Rapoport, Tom A., Roll-Mecak, Antonina, Rosen, Michael K., Rudenko, Gabby, Schlessinger, Joseph, Schwartz, Thomas U., Shamoo, Yousif, Sondermann, Holger, Tao, Yizhi J., Tolia, Niraj H., Tsodikov, Oleg V., Westover, Kenneth D., Wu, Hao, Foster, Ian, Fraser, James S., Maia, Filipe R N C, Gonen, Tamir, Kirchhausen, Tom, Diederichs, Kay, Crosas, Mercé, and Sliz, Piotr

Abstract

Access to experimental X-ray diffraction image data is fundamental for validation and reproduction of macromolecular models and indispensable for development of structural biology processing methods. Here, we established a diffraction data publication and dissemination system, Structural Biology Data Grid (SBDG; data.sbgrid.org), to preserve primary experimental data sets that support scientific publications. Data sets are accessible to researchers through a community driven data grid, which facilitates global data access. Our analysis of a pilot collection of crystallographic data sets demonstrates that the information archived by SBDG is sufficient to reprocess data to statistics that meet or exceed the quality of the original published structures. SBDG has extended its services to the entire community and is used to develop support for other types of biomedical data sets. It is anticipated that access to the experimental data sets will enhance the paradigm shift in the community towards a much more dynamic body of continuously improving data analysis.

Published
2016

22. Data publication with the structural biology data grid supports live analysis

Author

Sub NMR Spectroscopy, NMR Spectroscopy, Meyer, Peter A., Socias, Stephanie, Key, Jason, Ransey, Elizabeth, Tjon, Emily C., Buschiazzo, Alejandro, Lei, Ming, Botka, Chris, Withrow, James, Neau, David, Rajashankar, Kanagalaghatta, Anderson, Karen S., Baxter, Richard H., Blacklow, Stephen C., Boggon, Titus J., Bonvin, Alexandre M J J, Borek, Dominika, Brett, Tom J., Caflisch, Amedeo, Chang, Chung I., Chazin, Walter J., Corbett, Kevin D., Cosgrove, Michael S., Crosson, Sean, Dhe-Paganon, Sirano, Di Cera, Enrico, Drennan, Catherine L., Eck, Michael J., Eichman, Brandt F., Fan, Qing R., Ferré-D'Amaré, Adrian R., Fromme, J. Christopher, Garcia, K. Christopher, Gaudet, Rachelle, Gong, Peng, Harrison, Stephen C., Heldwein, Ekaterina E., Jia, Zongchao, Keenan, Robert J., Kruse, Andrew C., Kvansakul, Marc, McLellan, Jason S., Modis, Yorgo, Nam, Yunsun, Otwinowski, Zbyszek, Pai, Emil F., Pereira, Pedro José Barbosa, Petosa, Carlo, Raman, C. S., Rapoport, Tom A., Roll-Mecak, Antonina, Rosen, Michael K., Rudenko, Gabby, Schlessinger, Joseph, Schwartz, Thomas U., Shamoo, Yousif, Sondermann, Holger, Tao, Yizhi J., Tolia, Niraj H., Tsodikov, Oleg V., Westover, Kenneth D., Wu, Hao, Foster, Ian, Fraser, James S., Maia, Filipe R N C, Gonen, Tamir, Kirchhausen, Tom, Diederichs, Kay, Crosas, Mercé, Sliz, Piotr, Sub NMR Spectroscopy, NMR Spectroscopy, Meyer, Peter A., Socias, Stephanie, Key, Jason, Ransey, Elizabeth, Tjon, Emily C., Buschiazzo, Alejandro, Lei, Ming, Botka, Chris, Withrow, James, Neau, David, Rajashankar, Kanagalaghatta, Anderson, Karen S., Baxter, Richard H., Blacklow, Stephen C., Boggon, Titus J., Bonvin, Alexandre M J J, Borek, Dominika, Brett, Tom J., Caflisch, Amedeo, Chang, Chung I., Chazin, Walter J., Corbett, Kevin D., Cosgrove, Michael S., Crosson, Sean, Dhe-Paganon, Sirano, Di Cera, Enrico, Drennan, Catherine L., Eck, Michael J., Eichman, Brandt F., Fan, Qing R., Ferré-D'Amaré, Adrian R., Fromme, J. Christopher, Garcia, K. Christopher, Gaudet, Rachelle, Gong, Peng, Harrison, Stephen C., Heldwein, Ekaterina E., Jia, Zongchao, Keenan, Robert J., Kruse, Andrew C., Kvansakul, Marc, McLellan, Jason S., Modis, Yorgo, Nam, Yunsun, Otwinowski, Zbyszek, Pai, Emil F., Pereira, Pedro José Barbosa, Petosa, Carlo, Raman, C. S., Rapoport, Tom A., Roll-Mecak, Antonina, Rosen, Michael K., Rudenko, Gabby, Schlessinger, Joseph, Schwartz, Thomas U., Shamoo, Yousif, Sondermann, Holger, Tao, Yizhi J., Tolia, Niraj H., Tsodikov, Oleg V., Westover, Kenneth D., Wu, Hao, Foster, Ian, Fraser, James S., Maia, Filipe R N C, Gonen, Tamir, Kirchhausen, Tom, Diederichs, Kay, Crosas, Mercé, and Sliz, Piotr

Published
2016

23. Collaboration gets the most out of software

Author

Morin, Andrew, primary, Eisenbraun, Ben, additional, Key, Jason, additional, Sanschagrin, Paul C, additional, Timony, Michael A, additional, Ottaviano, Michelle, additional, and Sliz, Piotr, additional

Published
2013
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24. Allosteric inhibition of hypoxia inducible factor-2 with small molecules

Author

Scheuermann, Thomas H, primary, Li, Qiming, additional, Ma, He-Wen, additional, Key, Jason, additional, Zhang, Lei, additional, Chen, Rui, additional, Garcia, Joseph A, additional, Naidoo, Jacinth, additional, Longgood, Jamie, additional, Frantz, Doug E, additional, Tambar, Uttam K, additional, Gardner, Kevin H, additional, and Bruick, Richard K, additional

Published
2013
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25. Development of Inhibitors of the PAS-B Domain of the HIF-2α Transcription Factor

Author

Rogers, Jamie L., primary, Bayeh, Liela, additional, Scheuermann, Thomas H., additional, Longgood, Jamie, additional, Key, Jason, additional, Naidoo, Jacinth, additional, Melito, Lisa, additional, Shokri, Cameron, additional, Frantz, Doug E., additional, Bruick, Richard K., additional, Gardner, Kevin H., additional, MacMillan, John B., additional, and Tambar, Uttam K., additional

Published
2013
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30. Extraction of accurate structure-factor amplitudes from Laue data: wavelength normalization with wiggler and undulator X-ray sources

Author

Šrajer, Vukica, primary, Crosson, Sean, additional, Schmidt, Marius, additional, Key, Jason, additional, Schotte, Friedrich, additional, Anderson, Spencer, additional, Perman, Benjamin, additional, Ren, Zhong, additional, Teng, T.Y., additional, Bourgeois, Dominique, additional, Wulff, Michael, additional, and Moffat, Keith, additional

Published
2000
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33. Regulating the ARNT/TACC3 Axis: Multiple Approaches to Manipulating Protein/Protein Interactions with Small Molecules

Author

Guo, Yirui, Partch, Carrie L., Key, Jason, Card, Paul B., Pashkov, Victor, Patel, Anjana, Bruick, Richard K., Wurdak, Heiko, and Gardner, Kevin H.

Abstract

For several well-documented reasons, it has been challenging to develop artificial small molecule inhibitors of protein/protein complexes. Such reagents are of particular interest for transcription factor complexes given links between their misregulation and disease. Here we report parallel approaches to identify regulators of a hypoxia signaling transcription factor complex, involving the ARNT subunit of the HIF (Hypoxia Inducible Factor) activator and the TACC3 (Transforming Acidic Coiled Coil Containing Protein 3) coactivator. In one route, we used in vitroNMR and biochemical screening to identify small molecules that selectively bind within the ARNT PAS (Per-ARNT-Sim) domain that recruits TACC3, identifying KG-548 as an ARNT/TACC3 disruptor. A parallel, cell-based screening approach previously implicated the small molecule KHS101 as an inhibitor of TACC3 signaling. Here, we show that KHS101 works indirectly on HIF complex formation by destabilizing both TACC3 and the HIF component HIF-1α. Overall, our data identify small molecule regulators for this important complex and highlight the utility of pursuing parallel strategies to develop protein/protein inhibitors.

Published
2013
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34. The A.B.L.E. Model for Enhancing Diversity, Equity, and Inclusion.

Author

Johnson, Nathan and Key, Jason

Abstract

Hypothesis: The lack of practicing clinical laboratory professionals in the United States is alarming. Lab training programs have experienced stagnant or a reduction in class sizes with unfilled training seats. It was with this backdrop that the Medical Laboratory Sciences (MLS) Program at UAMS instituted the A.B.L.E. principles to increase class size and diversity of its MLS program. The A.B.L.E. principles were obtained by the Department Chair during his time in laboratory leadership roles in the Department of Defense. The A.B.L.E. principles include Attitude, Belief, Labor, and Equity. It was hypothesized that the UAMS MLS could grow in size and diversity using these principles. Method: The A.B.L.E. principles include Attitude, Belief, Labor, and Equity. The A.B.L.E. principles aligned with the overall UAMS and College of Health Professions Core Values. Observations/Outcomes: Utilization of the A.B.L.E. method were critical to enhancing our program's growth, retention of students, increase in test scores, an increase in the diversity, and drove a commitment to better support the underserved areas of lab medicine. Conclusion: Our department has become a model program by using the A.B.L.E. method. [ABSTRACT FROM AUTHOR]

Published
2021

35. Dynamics of carbon monoxide photodissociation in Bradyrhizobium japonicum FixL probed by picosecond midinfrared spectroscopy.

Author

van Wilderen LJ, Key JM, Van Stokkum IH, van Grondelle R, and Groot ML

Subjects
Heme chemistry, Hot Temperature, Kinetics, Models, Molecular, Molecular Conformation, Photochemistry, Photolysis, Solvents, Spectrophotometry, Infrared, Spectrophotometry, Ultraviolet, Thermodynamics, Bradyrhizobium chemistry, Carbon Monoxide chemistry
Abstract

The FixL proteins are heme-based bacterial oxygen sensors, distinct from globins in structure and ligand binding properties. To better understand the dynamics of ligand dissociation and binding within the PAS domain fold of FixL, we have carried out picosecond visible pump-midinfrared probe spectroscopy on the isolated PAS domain of FixL from Bradyrhizobium japonicum. We employ the diatomic ligand CO as a probe of the ligand-dissociation pocket dynamics; upon photoexcitation with a visible laser pulse, CO is released and the infrared-active stretch frequency of the CO molecule changes, as it is very sensitive to interactions with the surrounding protein. The infrared absorption difference spectra indicate that the escape of photolyzed CO to solvent is preceded by transient docking within the protein in a manner similar to globins. A small-scale spectral change of the CO molecule on a picosecond time scale is likely due to changes in heme-protein conformation associated with cooling. A larger scale spectral evolution on a nanosecond time scale indicates a structural change in the protein, possibly related to changes in the beta-strands associated with the transition from CO-bound to deoxy in BjFixLH (Key, J.; Srajer, V.; Pahl, R.; Moffat, K. Biochemistry 2007, 46, 4706).

Published
2009
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