title: Rational design of a beta-lactamase inhibitor achieved via stabilization of the trans-enamine intermediate: 1.28 A crystal structure of wt SHV-1 complex with a penam sulfone.
abstract: beta-Lactamases are one of the major causes of antibiotic resistance in Gram negative bacteria. The continuing evolution of beta-lactamases that are capable of hydrolyzing our most potent beta-lactams presents a vexing clinical problem, in particular since a number of them are resistant to inhibitors. The efficient inhibition of these enzymes is therefore of great clinical importance. Building upon our previous structural studies that examined tazobactam trapped as a trans-enamine intermediate in a deacylation deficient SHV variant, we designed a novel penam sulfone derivative that forms a more stable trans-enamine intermediate. We report here the 1.28 A resolution crystal structure of wt SHV-1 in complex with a rationally designed penam sulfone, SA2-13. The compound is covalently bound to the active site of wt SHV-1 similar to tazobactam yet forms an additional salt-bridge with K234 and hydrogen bonds with S130 and T235 to stabilize the trans-enamine intermediate. Kinetic measurements show that SA2-13, once reacted with SHV-1 beta-lactamase, is about 10-fold slower at being released from the enzyme compared to tazobactam. Stabilizing the trans-enamine intermediate represents a novel strategy for the rational design of mechanism-based class A beta-lactamase inhibitors.
authors.affiliation: Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio 44106, USA.
authors.forename: Pius S
authors.initials: PS
authors.lastname: Padayatti
authors.forename: Anjaneyulu
authors.initials: A
authors.lastname: Sheri
authors.forename: Monica A
authors.initials: MA
authors.lastname: Totir
authors.forename: Marion S
authors.initials: MS
authors.lastname: Helfand
authors.forename: Marianne P
authors.initials: MP
authors.lastname: Carey
authors.forename: Vernon E
authors.initials: VE
authors.lastname: Anderson
authors.forename: Paul R
authors.initials: PR
authors.lastname: Carey
authors.forename: Christopher R
authors.initials: CR
authors.lastname: Bethel
authors.forename: Robert A
authors.initials: RA
authors.lastname: Bonomo
authors.forename: John D
authors.initials: JD
authors.lastname: Buynak
authors.forename: Focco
authors.initials: F
authors.lastname: van den Akker
mesh_terms: D000588:Amines / Q000737:chemistry; D001665:Binding Sites; D018360:Crystallography, X-Ray; D015195:Drug Design; D004355:Drug Stability; D004791:Enzyme Inhibitors / Q000737:chemistry* / Q000494:pharmacology; D007700:Kinetics; D008958:Models, Molecular; D010397:Penicillanic Acid / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D011487:Protein Conformation; D013450:Sulfones / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology; D000078142:Tazobactam; D065093:beta-Lactamase Inhibitors; D001618:beta-Lactamases / Q000737:chemistry
chemical_list: D000588:Amines; D004791:Enzyme Inhibitors; C000591536:SA2-13 compound; D013450:Sulfones; D065093:beta-Lactamase Inhibitors; D010397:Penicillanic Acid; C054882:beta-lactamase PIT-2; D001618:beta-Lactamases; D000078142:Tazobactam