title: Allosteric competitive inhibitors of the glucose-1-phosphate thymidylyltransferase (RmlA) from Pseudomonas aeruginosa.
abstract: Glucose-1-phosphate thymidylyltransferase (RmlA) catalyzes the condensation of glucose-1-phosphate (G1P) with deoxy-thymidine triphosphate (dTTP) to yield dTDP-d-glucose and pyrophosphate. This is the first step in the l-rhamnose biosynthetic pathway. l-Rhamnose is an important component of the cell wall of many microorganisms, including Mycobacterium tuberculosis and Pseudomonas aeruginosa. Here we describe the first nanomolar inhibitors of P. aeruginosa RmlA. These thymine analogues were identified by high-throughput screening and subsequently optimized by a combination of protein crystallography, in silico screening, and synthetic chemistry. Some of the inhibitors show inhibitory activity against M. tuberculosis. The inhibitors do not bind at the active site of RmlA but bind at a second site remote from the active site. Despite this, the compounds act as competitive inhibitors of G1P but with high cooperativity. This novel behavior was probed by structural analysis, which suggests that the inhibitors work by preventing RmlA from undergoing the conformational change key to its ordered bi-bi mechanism.
authors.affiliation: Biomedical Sciences Research Complex,  University of St. Andrews , St. Andrews KY16 9ST, U.K.
authors.forename: Magnus S
authors.initials: MS
authors.lastname: Alphey
authors.forename: Lisa
authors.initials: L
authors.lastname: Pirrie
authors.forename: Leah S
authors.initials: LS
authors.lastname: Torrie
authors.forename: Wassila Abdelli
authors.initials: WA
authors.lastname: Boulkeroua
authors.forename: Mary
authors.initials: M
authors.lastname: Gardiner
authors.forename: Aurijit
authors.initials: A
authors.lastname: Sarkar
authors.forename: Marko
authors.initials: M
authors.lastname: Maringer
authors.forename: Wulf
authors.initials: W
authors.lastname: Oehlmann
authors.forename: Ruth
authors.initials: R
authors.lastname: Brenk
authors.forename: Michael S
authors.initials: MS
authors.lastname: Scherman
authors.forename: Michael
authors.initials: M
authors.lastname: McNeil
authors.forename: Martin
authors.initials: M
authors.lastname: Rejzek
authors.forename: Robert A
authors.initials: RA
authors.lastname: Field
authors.forename: Mahavir
authors.initials: M
authors.lastname: Singh
authors.forename: David
authors.initials: D
authors.lastname: Gray
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Westwood
authors.forename: James H
authors.initials: JH
authors.lastname: Naismith
mesh_terms: D000495:Allosteric Site / Q000187:drug effects; D001667:Binding, Competitive / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D057166:High-Throughput Screening Assays; D008958:Models, Molecular; D015394:Molecular Structure; D009713:Nucleotidyltransferases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D011550:Pseudomonas aeruginosa / Q000201:enzymology*; D013329:Structure-Activity Relationship; D013941:Thymine / Q000031:analogs & derivatives / Q000737:chemistry / Q000494:pharmacology*
chemical_list: D004791:Enzyme Inhibitors; D009713:Nucleotidyltransferases; C020587:glucose-1-phosphate thymidylyltransferase; D013941:Thymine