title: Heterocyclic bis-cations as starting hits for design of inhibitors of the bifunctional enzyme histidine-containing protein kinase/phosphatase from Bacillus subtilis.
abstract: The main mechanism of carbon catabolite repression/activation in low-guanine and low-cytosine Gram-positive bacteria seems to involve phosphorylation of HPr (histidine-containing protein) at Ser-46 by the ATP-dependent HPr kinase, which in Bacillus subtilis, Lactobacillus casei, and Staphylococcus xylosus also exhibits phosphatase activity and is thus a bifunctional enzyme (HPrK/P). Since deficiency of HPrK/P in S. xylosus, L. casei, and B. subtilis mutants leads to severe growth defects, inhibitors of the enzyme could form a new family of antibiotic drugs. The aim of the study was to screen an in-house chemical library for identification of hits as inhibitors of HPrK/P in B. subtilis and to further extract additional information of structural features from hit optimization using a radioactive in vitro assay. A symmetrical bis-cationic compound LPS 02-10-L-D09 (2a) with a 12-carbon alkyl linker bridging the two 2-aminobenzimidazole moieties was identified as a non-ATP mimetic compound exhibiting an EC(50) value of 10 microM in a kinase assay with HPr as substrate. The substance also inhibited the phosphatase activity of HPrK/P triggered by the addition of inorganic phosphate. Similar results were obtained with 2a and catabolite repression HPr, which, like HPr, can be phosphorylated at Ser-46 by HPrK/P and is involved in catabolite repression. Structure-activity relationship analysis indicated the importance in its structure of a substituted 2-aminobenzimidazole. This typical heterocycle is linked through a C12 alkyl chain to a second scaffold that can bear a cationic or a noncationic moiety but in all cases should present an aromatic ring in its vicinity.
authors.affiliation: Pharmacologie et Physico-Chimie des Interactions Cellulaires et Moléculaires, Université Louis Pasteur de Strasbourg, Faculté de Pharmacie, 74 Route du Rhin, B.P. 24, F-67401 Illkirch, France.
authors.forename: Helena
authors.initials: H
authors.lastname: Ramström
authors.forename: Maryline
authors.initials: M
authors.lastname: Bourotte
authors.forename: Claude
authors.initials: C
authors.lastname: Philippe
authors.forename: Martine
authors.initials: M
authors.lastname: Schmitt
authors.forename: Jacques
authors.initials: J
authors.lastname: Haiech
authors.forename: Jean-Jacques
authors.initials: JJ
authors.lastname: Bourguignon
mesh_terms: D000255:Adenosine Triphosphate / Q000737:chemistry; D001412:Bacillus subtilis / Q000737:chemistry*; D001562:Benzimidazoles / Q000138:chemical synthesis* / Q000493:pharmacokinetics / Q000494:pharmacology; D002412:Cations; D020650:Combinatorial Chemistry Techniques; D016208:Databases, Factual; D015195:Drug Design; D004347:Drug Interactions; D006574:Heterocyclic Compounds, 2-Ring / Q000138:chemical synthesis* / Q000737:chemistry; D000071677:Histidine Kinase; D010744:Phosphoric Monoester Hydrolases / Q000037:antagonists & inhibitors* / Q000737:chemistry; D010766:Phosphorylation; D047428:Protein Kinase Inhibitors; D011494:Protein Kinases / Q000737:chemistry; D013329:Structure-Activity Relationship
chemical_list: D001562:Benzimidazoles; D002412:Cations; D006574:Heterocyclic Compounds, 2-Ring; C485230:N,N'-bis(2-amino-1-benzylbenzimidazol-3-yl)-1,12-dodecane; D047428:Protein Kinase Inhibitors; D000255:Adenosine Triphosphate; D011494:Protein Kinases; D000071677:Histidine Kinase; D010744:Phosphoric Monoester Hydrolases