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10. Role of Tyrosine 65 in the mechanism of serine hydroxymethyltransferase

Author

Contestabile, Roberto, Angelaccio, Sebastiana, Bossa, Francesco, Wright, H. Tonie, Scarsdale, Neel, Kazanina, Galina, and Schirch, Verne

Subjects
Biochemistry -- Research, Biological sciences, Chemistry
Abstract

Role of Tyrosine 65 in the mechanism of serine hydroxymethyltransferase.

Published
2000

15. Purification and properties of serine hydroxymethyltransferase from Sulfolobus solfataricus

Author

Fratte, Sonia Delle, White, Robert H., Maras, Bruno, Bossa, Francesco, and Schirch, Verne

Subjects
Serine -- Research, Bacteria, Thermophilic -- Research, Enzymes -- Research, Biological sciences
Abstract

Research was conducted to study the purification and characterization of serine hydroxymthyltransferase (SHMT) from the thermophilic organism Sulfolobus solfataricus. SHMT activity was determined by monitoring the rate of exchange of the alpha-hydrogen of (2-(super 3)H)glycine while a Superdex 200 column was utilized to chromatograph the enzyme from several purification steps. Results showed similarities in the size and properties of the S. solfataricus SHMT relative to procaryotic and eucaryotic SHMT.

Published
1997

19. Conclusions

Author

Bossa, Francesco, Marino, G., editor, Sannia, G., editor, and Bossa, F., editor

Published
1994
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26. Serine hydroxymethyltransferase: origin of substrate specificity

Author

Angelaccio, Sebastiana, Pascarella, Stefano, Fattori, Elena, Bossa, Francesco, Strong, William, and Schirch, Verne

Subjects
Methyltransferases -- Research, Serine -- Research, Mutagenesis -- Usage, Biological sciences, Chemistry
Abstract

The function of each of the five threonine residues of the Escherichia coli serine hydroxymethyltransferase was determined. Site-directed mutagenesis was used to substitute each Thr with Ala. The mutants produced were purified and characterized with respect to affinity of coenzymes, substrates and substrate analogues. The most significant enzyme produced was the T226A which plays an important role in the conversion of the gem-diamine complex to the external aldimine complex.

Published
1992

40. The role of evolutionarily conserved hydrophobic contacts in the quaternary structure stability of Escherichia coli serine hydroxymethyltransferase

Author

Florio, Rita, Chiaraluce, Roberta, Consalvi, Valerio, Paiardini, Alessandro, Catacchio, B, Bossa, Francesco, and Contestabile, Roberto

Subjects
Glycine Hydroxymethyltransferase, Models, Molecular, Binding Sites, Protein Conformation, Escherichia coli Proteins, Recombinant Proteins, Evolution, Molecular, Kinetics, Apoenzymes, Amino Acid Substitution, Pyridoxal Phosphate, Enzyme Stability, Escherichia coli, Mutagenesis, Site-Directed, Protein Structure, Quaternary
Abstract

Pyridoxal 5'-phosphate-dependent enzymes may be grouped into five structural superfamilies of proteins, corresponding to as many fold types. The fold type I is by far the largest and most investigated group. An important feature of this fold, which is characterized by the presence of two domains, appears to be the existence of three clusters of evolutionarily conserved hydrophobic contacts. Although two of these clusters are located in the central cores of the domains and presumably stabilize their scaffold, allowing the correct alignment of the residues involved in cofactor and substrate binding, the role of the third cluster is much less evident. A site-directed mutagenesis approach was used to carry out a model study on the importance of the third cluster in the structure of a well characterized member of the fold type I group, serine hydroxymethyltransferase from Escherichia coli. The experimental results obtained indicated that the cluster plays a crucial role in the stabilization of the quaternary, native assembly of the enzyme, although it is not located at the subunit interface. The analysis of the crystal structure of serine hydroxymethyltransferase suggested that this stabilizing effect may be due to the strict structural relation between the cluster and two polypeptide loops, which, in fold type I enzymes, mediate the interactions between the subunits and are involved in cofactor binding, substrate binding and catalysis.

Published
2008

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