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Title: Sent packing: protein engineering generates a new crystal form of Pseudomonas aeruginosa DsbA1 with increased catalytic surface accessibility

The crystal structure of a P. aeruginosa DsbA1 variant is more suitable for fragment-based lead discovery efforts to identify inhibitors of this antimicrobial drug target. In the reported structures the active site of the protein can simultaneously bind multiple ligands introduced in the crystallization solution or via soaking. Pseudomonas aeruginosa is an opportunistic human pathogen for which new antimicrobial drug options are urgently sought. P. aeruginosa disulfide-bond protein A1 (PaDsbA1) plays a pivotal role in catalyzing the oxidative folding of multiple virulence proteins and as such holds great promise as a drug target. As part of a fragment-based lead discovery approach to PaDsbA1 inhibitor development, the identification of a crystal form of PaDsbA1 that was more suitable for fragment-soaking experiments was sought. A previously identified crystallization condition for this protein was unsuitable, as in this crystal form of PaDsbA1 the active-site surface loops are engaged in the crystal packing, occluding access to the target site. A single residue involved in crystal-packing interactions was substituted with an amino acid commonly found at this position in closely related enzymes, and this variant was successfully used to generate a new crystal form of PaDsbA1 in which the active-site surface is more accessible formore » soaking experiments. The PaDsbA1 variant displays identical redox character and in vitro activity to wild-type PaDsbA1 and is structurally highly similar. Two crystal structures of the PaDsbA1 variant were determined in complex with small molecules bound to the protein active site. These small molecules (MES, glycerol and ethylene glycol) were derived from the crystallization or cryoprotectant solutions and provide a proof of principle that the reported crystal form will be amenable to co-crystallization and soaking with small molecules designed to target the protein active-site surface.« less
Authors:
; ; ;  [1] ;  [2] ;  [3] ;  [1]
  1. University of Queensland, 306 Carmody Road, Brisbane, Queensland 4072 (Australia)
  2. Biota Holdings Limited, Unit 10, 585 Blackburn Road, Notting Hill, Victoria 3168 (Australia)
  3. Monash University, 381 Royal Parade, Parkville, Victoria 3052 (Australia)
Publication Date:
OSTI Identifier:
22515198
Resource Type:
Journal Article
Resource Relation:
Journal Name: Acta Crystallographica. Section D: Biological Crystallography; Journal Volume: 71; Journal Issue: Pt 12; Other Information: PMCID: PMC4667283; PMID: 26627647; PUBLISHER-ID: gm5040; OAI: oai:pubmedcentral.nih.gov:4667283; Copyright (c) McMahon et al. 2015; This is an open-access article distributed under the terms of the Creative Commons Attribution Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
Denmark
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; AMINO ACIDS; CRYSTAL STRUCTURE; CRYSTALLIZATION; MATHEMATICAL SOLUTIONS; MOLECULES; STOWING; SURFACES