title: Novel Computational Protocols for Functionally Classifying and Characterising Serine Beta-Lactamases.
abstract: Beta-lactamases represent the main bacterial mechanism of resistance to beta-lactam antibiotics and are a significant challenge to modern medicine. We have developed an automated classification and analysis protocol that exploits structure- and sequence-based approaches and which allows us to propose a grouping of serine beta-lactamases that more consistently captures and rationalizes the existing three classification schemes: Classes, (A, C and D, which vary in their implementation of the mechanism of action); Types (that largely reflect evolutionary distance measured by sequence similarity); and Variant groups (which largely correspond with the Bush-Jacoby clinical groups). Our analysis platform exploits a suite of in-house and public tools to identify Functional Determinants (FDs), i.e. residue sites, responsible for conferring different phenotypes between different classes, different types and different variants. We focused on Class A beta-lactamases, the most highly populated and clinically relevant class, to identify FDs implicated in the distinct phenotypes associated with different Class A Types and Variants. We show that our FunFHMMer method can separate the known beta-lactamase classes and identify those positions likely to be responsible for the different implementations of the mechanism of action in these enzymes. Two novel algorithms, ASSP and SSPA, allow detection of FD sites likely to contribute to the broadening of the substrate profiles. Using our approaches, we recognise 151 Class A types in UniProt. Finally, we used our beta-lactamase FunFams and ASSP profiles to detect 4 novel Class A types in microbiome samples. Our platforms have been validated by literature studies, in silico analysis and some targeted experimental verification. Although developed for the serine beta-lactamases they could be used to classify and analyse any diverse protein superfamily where sub-families have diverged over both long and short evolutionary timescales.
authors.affiliation: Institute of Structural and Molecular Biology, University College London, London, United Kingdom.
authors.forename: David
authors.identifier: 0000-0003-1794-2232
authors.initials: D
authors.lastname: Lee
authors.affiliation: Institute of Structural and Molecular Biology, University College London, London, United Kingdom.
authors.forename: Sayoni
authors.initials: S
authors.lastname: Das
authors.affiliation: Institute of Structural and Molecular Biology, University College London, London, United Kingdom.
authors.forename: Natalie L
authors.initials: NL
authors.lastname: Dawson
authors.affiliation: Department of Biochemical Engineering, University College London, London, United Kingdom.
authors.forename: Dragana
authors.initials: D
authors.lastname: Dobrijevic
authors.affiliation: Department of Biochemical Engineering, University College London, London, United Kingdom.
authors.forename: John
authors.identifier: 0000-0002-4415-5544
authors.initials: J
authors.lastname: Ward
authors.affiliation: Institute of Structural and Molecular Biology, University College London, London, United Kingdom.
authors.forename: Christine
authors.initials: C
authors.lastname: Orengo
mesh_terms: D000465:Algorithms; D001665:Binding Sites; D003198:Computer Simulation; D024881:Drug Resistance, Bacterial; D004789:Enzyme Activation; D062105:Molecular Docking Simulation / Q000379:methods*; D011485:Protein Binding; D020539:Sequence Analysis, Protein / Q000379:methods*; D012694:Serine; D012984:Software; D013329:Structure-Activity Relationship; D013379:Substrate Specificity; D018440:beta-Lactam Resistance; D065093:beta-Lactamase Inhibitors / Q000737:chemistry; D001618:beta-Lactamases / Q000737:chemistry* / Q000648:ultrastructure*
chemical_list: D065093:beta-Lactamase Inhibitors; D012694:Serine; D001618:beta-Lactamases