Please use this identifier to cite or link to this item: http://hdl.handle.net/10397/68571
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dc.contributor.authorPan, XHen_US
dc.contributor.authorHe, YJen_US
dc.contributor.authorLei, JPen_US
dc.contributor.authorHuang, XHen_US
dc.contributor.authorZhao, YXen_US
dc.date.accessioned2017-08-29T03:41:31Z-
dc.date.available2017-08-29T03:41:31Z-
dc.date.issued2017-
dc.identifier.citationJournal of biological chemistry, 2017, v. 292, no. 10, p. 4022-4033en_US
dc.identifier.issn0021-9258en_US
dc.identifier.urihttp://hdl.handle.net/10397/68571-
dc.description.abstractbeta-Lactamases confer resistance to beta-lactam-based antibiotics. There is great interest in understanding their mechanisms to enable the development of beta-lactamase-specific inhibitors. The mechanism of class A beta-lactamases has been studied extensively, revealing Lys-73 and Glu-166 as general bases that assist the catalytic residue Ser-70. However, the specific roles of these two residues within the catalytic cycle remain not fully understood. To help resolve this, we first identified an E166H mutant that is functional but is kinetically slow. We then carried out time-resolved crystallographic study of a full cycle of the catalytic reaction. We obtained structures that represent apo, ES*-acylation, and ES*-deacylation states and analyzed the conformational changes of His-166. The "in" conformation in the apo structure allows His-166 to form a hydrogen bond with Lys-73. The unexpected "flipped-out" conformation of His-166 in the ES*-acylation structure was further examined by molecular dynamics simulations, which suggested deprotonated Lys-73 serving as the general base for acylation. The "revert-in" conformation in the ES*-deacylation structure aligns His-166 toward the water molecule that hydrolyzes the acyl adduct. Finally, when the acyl adduct is fully hydrolyzed, His-166 rotates back to the "in" conformation of the apo-state, restoring the Lys-73/ His-166 interaction. Using His-166 as surrogate, our study identifies distinct conformational changes within the active site during catalysis. We suggest that the native Glu-166 executes similar changes in a less constricted way. Taken together, this structural series improves our understanding of beta-lactam hydrolysis in this important class of enzymes.en_US
dc.description.sponsorshipDepartment of Applied Biology and Chemical Technologyen_US
dc.language.isoenen_US
dc.publisherAmerican Society for Biochemistry and Molecular Biologyen_US
dc.relation.ispartofJournal of biological chemistryen_US
dc.titleCrystallographic snapshots of Class A beta-Lactamase catalysis reveal structural changes that facilitate beta-Lactam hydrolysisen_US
dc.typeJournal/Magazine Articleen_US
dc.identifier.spage4022en_US
dc.identifier.epage4033en_US
dc.identifier.volume292en_US
dc.identifier.issue10en_US
dc.identifier.doi10.1074/jbc.M116.764340en_US
dc.identifier.isiWOS:000395837100006-
dc.identifier.pmid28100776-
dc.source.typeArticleen
dc.identifier.eissn1083-351Xen_US
item.fulltextFull Text (via PolyU elinks)-
crisitem.author.deptDepartment of Applied Biology and Chemical Technology-
crisitem.author.facultyFaculty of Applied Science and Textiles-
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