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Initial and final coordinates used and obtained in MD simulations forfree N-terminal truncated evasins and in complex with CCL17.&nbsp

Autotransporters (ATs) are a large family of bacterial secreted and outer membrane proteins that encompass a wide range of enzymatic activities frequently associated with pathogenic phenotypes. We present the structural and functional characterisation of a subtilase autotransporter, Ssp, from the opportunistic pathogen Serratia marcescens. Although the structures of subtilases have been well documented, this subtilisin-like protein is associated with a 248 residue β-helix and itself includes three finger-like protrusions around its active site involved in substrate interactions. We further reveal that the activity of the subtilase AT is required for entry into epithelial cells as well as causing cellular toxicity. The Ssp structure not only provides details about the subtilase ATs, but also reveals a common framework and function to more distantly related ATs. As such these findings also represent a significant step forward toward understanding the molecular mechanisms underlying the functional divergence in the large AT superfamily.

Shiva Shahriari,1 Murali Sastry,2 Santosh Panjikar,3,4 RK Singh Raman1 1Department of Mechanical & Aerospace Engineering, Monash University, Melbourne, Victoria, Australia; 2Department of Materials Science and Engineering, Monash University, Melbourne, Victoria, Australia; 3ANSTO, Australian Synchrotron, Melbourne, Victoria, Australia; 4Department of Molecular Biology and Biochemistry, Monash University, Melbourne, Victoria, AustraliaCorrespondence: RK Singh RamanDepartment of Mechanical and Aerospace Engineering, Monash University, 17 College Walk (Building 31), Melbourne, Victoria, 3800, AustraliaTel +61 3 9905 3545Fax +61 3 9905 1825Email raman.singh@monash.eduSantosh PanjikarANSTO, Australian Synchrotron, 800 Blackburn Road, Melbourne, Victoria, 3168, AustraliaTel +61 3 8540 4276Email santosh.panjikar@ansto.gov.auAbstract: Graphene and graphene oxide have become the base of many advanced biosensors due to their exceptional characteristics. However, lack of some properties, such as inertness of graphene in organic solutions and non-electrical conductivity of graphene oxide, are their drawbacks in sensing applications. To compensate for these shortcomings, various methods of modifications have been developed to provide the appropriate properties required for biosensing. Efficient modification of graphene and graphene oxide facilitates the interaction of biomolecules with their surface, and the ultimate bioconjugate can be employed as the main sensing part of the biosensors. Graphene nanomaterials as transducers increase the signal response in various sensing applications. Their large surface area and perfect biocompatibility with lots of biomolecules provide the prerequisite of a stable biosensor, which is the immobilization of bioreceptor on transducer. Biosensor development has paramount importance in the field of environmental monitoring, security, defense, food safety standards, clinical sector, marine sector, biomedicine, and drug discovery. Biosensor applications are also prevalent in the plant biology sector to find the missing links required in the metabolic process. In this review, the importance of oxygen functional groups in functionalizing the graphene and graphene oxide and different types of functionalization will be explained. Moreover, immobilization of biomolecules (such as protein, peptide, DNA, aptamer) on graphene and graphene oxide and at the end, the application of these biomaterials in biosensors with different transducing mechanisms will be discussed.Keywords: functionalization, immobilization, oxygen functional groups, bioconjugate

Bacteria respond to environmental changes by inducing transcription of some genes and repressing others. Sialic acids, which coat human cell surfaces, are a nutrient source for pathogenic and commensal bacteria. TheEscherichia coliGntR-type transcriptional repressor, NanR, regulates sialic acid metabolism, but the mechanism is unclear. Here, we demonstrate that three NanR dimers bind a (GGTATA)3-repeat operator cooperatively and with high affinity. Truncation of an N-terminal extension abolishes cooperative binding. The effector,N-acetylneuraminate, binds NanR and attenuates DNA binding. Crystal structure data show thatN-acetylneuraminate binding to NanR causes a domain rearrangement that locks the protein in a conformation that prevents DNA binding. Single-particle cryo-electron microscopy structures of NanR bound to DNA reveal the DNA binding domain is reorganized to engage DNA, while the three dimers assemble in close proximity across the (GGTATA)3-repeat operator allowing protein-protein interactions to formviathe N-terminal extensions. Our data provides a molecular basis for the regulation of bacterial sialic acid metabolism.

MASSIVE is the Australian specialised High Performance Computing facility for imaging and visualisation. The project is a collaboration between Monash University, Australian Synchrotron and CSIRO. MASSIVE underpins a range of advanced instruments, with a particular focus on Australian Synchrotron beamlines. This paper will report on the outcomes of the MASSIVE project since 2011, in particular focusing on instrument integration, and interactive access. MASSIVE has developed a unique capability that supports an increasing number of researchers generating and processing instrument data. The facility runs an instrument integration program to help facilities move data to an HPC environment and provide in-experiment data processing. This capability is best demonstrated at the Imaging and Medical Beamline where fast CT reconstruction and visualisation is now essential to performing effective experiments. The MASSIVE Desktop provides an easy method for researchers to begin using HPC, and is now an essential tool for scientists working with large datasets, including large images and other types of instrument data., Proceedings of the 15th Int. Conf. on Accelerator and Large Experimental Physics Control Systems, ICALEPCS2015, Melbourne, Australia

Ubiquitin-conjugating enzymes (E2s) coordinate distinct types of ubiquitination via specific E3 ligases, to a large number of protein substrates. While many E2 enzymes need only the presence of an E3 ligase for substrate ubiquitination, a number of E2s require additional, non-canonical binding partners to specify their function. Here, we have determined the crystal structure and function of an E2/co-activator assembly, the Pex4p:Pex22p complex. The peroxisome-associated E2 enzyme Pex4p binds the peroxisomal membrane protein Pex22p through a binding site that does not overlap with any other known interaction interface in E2 enzymes. Pex22p association enhances Pex4p's ability to transfer ubiquitin to a substrate in vitro, and Pex22p binding-deficient forms of Pex4p are unable to ubiquitinate the peroxisomal import receptor Pex5p in vivo. Our data demonstrate that the Pex4p:Pex22p assembly, and not Pex4p alone, functions as the E2 enzyme required for Pex5p ubiquitination, establishing a novel mechanism of E2 enzyme regulation. The EMBO Journal (2012) 31, 391-402. doi:10.1038/emboj.2011.411; Published online 15 November 2011