title: Conformational analyses and MO studies of f152A1 and its analogues as potent protein kinase inhibitors.
abstract: f152A1 was isolated from a fermentation broth of Curvularia verruculosa and characterized as a potent inhibitor of TNFalpha transcription, with anti-inflammatory activity. f152A1 and several analogues displayed inhibitory activity against the MAP kinases ERK2 and MEK1 in in vitro kinase assays. Through SAR studies on f152A1 and analogues prepared via total synthesis, we have identified structural features that contribute to inhibitory activity. To rationalize these results and to aid in the discovery process, a combination of high temperature molecular dynamics and MOPAC AM1 semiempirical molecular orbital method studies was used in studies that yielded a postulated active conformation, M1(8). This active conformation M1(8) reflects a high degree of conformational similarity among f152A1 and its more potent analogues. In view of the highly reactive cis-enone moiety in the flexible 14-membered resorcylic acid lactone ring of f152A1, the chemical reactivities of the enone moieties in various analogues were assessed by molecular orbital calculations. The enone reactivity analyses suggested that these inhibitors were prone to Michael addition at the alpha,beta-unsaturated ketone moiety and might chemically react with cysteine residues in the ATP-binding site of MAP kinases. Reactivity of the cis-enone moiety and the M1(8) conformation make important contributions to the inhibitory activity of MAP kinases.
authors.affiliation: Eisai Tsukuba Research Laboratories, 1-3, Tokodai 5-chome, Tsukuba-shi, Ibaraki 300-2635, Japan.
authors.forename: Megumi
authors.initials: M
authors.lastname: Ikemori-Kawada
authors.forename: Takatoshi
authors.initials: T
authors.lastname: Kawai
authors.forename: Masaki
authors.initials: M
authors.lastname: Goto
authors.forename: Yuan John
authors.initials: YJ
authors.lastname: Wang
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Kawakami
mesh_terms: D000595:Amino Acid Sequence; D055808:Drug Discovery; D006801:Humans; D006878:Hydroxides / Q000737:chemistry; D007783:Lactones / Q000737:chemistry* / Q000494:pharmacology*; D048369:MAP Kinase Kinase 1 / Q000037:antagonists & inhibitors* / Q000737:chemistry; D019950:Mitogen-Activated Protein Kinase 1 / Q000037:antagonists & inhibitors* / Q000737:chemistry; D008958:Models, Molecular; D008968:Molecular Conformation; D008969:Molecular Sequence Data; D047428:Protein Kinase Inhibitors / Q000031:analogs & derivatives / Q000737:chemistry / Q000494:pharmacology*; D013237:Stereoisomerism; D013696:Temperature
chemical_list: D006878:Hydroxides; C118715:LL Z1640-2; D007783:Lactones; D047428:Protein Kinase Inhibitors; C031356:hydroxide ion; D019950:Mitogen-Activated Protein Kinase 1; D048369:MAP Kinase Kinase 1