@article {2193, title = {Mechanistic studies on PseB of pseudaminic acid biosynthesis: A UDP-N-acetylglucosamine 5-inverting 4,6-dehydratase}, journal = {Bioorganic Chemistry}, volume = {36}, number = {4-6}, year = {2008}, note = {ISI Document Delivery No.: 386TPTimes Cited: 2Cited Reference Count: 33Morrison, James P. Schoenhofen, Ian C. Tanner, Martin E.}, month = {Aug-Dec}, pages = {312-320}, type = {Article}, abstract = {UDP-N-acetylglucosamine 5-inverting 4,6-dehydratase (PseB) is a unique sugar nucleotide dehydratase that inverts the C-5 {\textquoteright}{\textquoteright} stereocentre during conversion of UDP-N-acetylglucosamine to UDP-2-acetamido2,6-dideoxy-beta-L-arabino-hexos-4-ulose. PseB catalyzes the first step in the biosynthesis of pseudaminic acid, which is found as a post-translational modification on the flagellin of Campylobacter jejuni and Helicobacter pylori. PseB is proposed to use its tightly bound NADP(+) to oxidize UDP-GlcNAc at C-4 {\textquoteright}{\textquoteright}, enabling dehydration. The alpha,beta unsaturated ketone intermediate is then reduced by delivery of the hydride to C-6 {\textquoteright}{\textquoteright} and a proton to C-5 {\textquoteright}{\textquoteright}. Consistent with this, PseB from C. jejuni has been found to incorporate deuterium into the C-5 {\textquoteright}{\textquoteright} position of product during catalysis in D2O. Likewise, PseB catalyzes solvent isotope exchange into the H-5 {\textquoteright}{\textquoteright} position of product, and eliminates HF from the alternate Substrate, UDP-6-deoxy-6-fluoro-GlcNAc. Mutants of the putative catalytic residues aspartate 126, lysine 127 and tyrosine 135 have severely compromised dehydratase, solvent isotope exchange, and HF elimination activities. (C) 2008 Elsevier Inc. All rights reserved.}, keywords = {6-DEHYDRATASE, Campylobacter jejuni, CAMPYLOBACTER-JEJUNI, dehydratase, DTDP-GLUCOSE 4, ENZYMES, FLAA1, FUNCTIONAL-CHARACTERIZATION, GDP-MANNOSE 4, HELICOBACTER-PYLORI, IDENTIFICATION, Inverting, MOTILITY, PATHWAY, PseB, Pseudaminic acid, UDP-N-acetylglucosamine 5-inverting 4}, isbn = {0045-2068}, url = {://000261905800019}, author = {Morrison, J. P. and Schoenhofen, I. C. and Tanner, M. E.} } @article {1198, title = {Strongylophorine-26, a Rho-dependent inhibitor of tumor cell invasion that reduces actin stress fibers and induces nonpolarized lamellipodial extensions}, journal = {Molecular Cancer Therapeutics}, volume = {4}, number = {5}, year = {2005}, note = {ISI Document Delivery No.: 926DETimes Cited: 6Cited Reference Count: 37}, month = {May}, pages = {772-778}, type = {Article}, abstract = {Strongylophorine-26, a new meroditerpenoid, was recently identified as an inhibitor of cancer cell invasion. This study was undertaken to characterize its mechanism of action. We find that strongylophorine-26 inhibits the motility of MDA-MB-231 breast carcinoma cells on a plastic surface. Upon addition of strongylophorine-26, rapid cell contraction and depolarization occurred, followed by spreading and flattening of the entire cell. Treated cells exhibited increased membrane ruffling throughout and extended lamellipodia in all directions. Strongylophorine-26 induced a decrease in actin stress fibers, a dramatic increase in the size and number of focal adhesions, and the appearance of a dense meshwork of actin filaments around the cell periphery. Strongylophorine-26 caused a transient activation of the small GTPase Rho and treatment with the Rho inhibitor C3 exoenzyme abrogated the anti-invasive activity of strongylophorine-26. These effects are distinct from those of many motility and angiogenesis inhibitors that seem to act by a common mechanism involving the induction of actin stress fibers. This difference in mechanism of action sets strongylophorine-26 apart as an experimental anticancer agent and indicates that pharmacologic inhibition of cell migration may be achieved by mechanisms not involving the stabilization of actin stress fibers.}, keywords = {ACTIVATION, ANGIOGENESIS, CYTOSKELETON, FAMILY, FOCAL ADHESIONS, KINASE, MIGRATION, MOTILITY, PROTEIN, SMALL GTPASE}, isbn = {1535-7163}, url = {://000229102300009}, author = {McHardy, L. M. and Warabi, K. and Andersen, R. J. and Roskelley, C. D. and Roberge, M.} } @article {643, title = {From the first to the second domain of gelsolin: a common path on the surface of actin?}, journal = {Febs Letters}, volume = {552}, number = {2-3}, year = {2003}, note = {ISI Document Delivery No.: 726DKTimes Cited: 22Cited Reference Count: 29}, month = {Sep}, pages = {86-90}, type = {Article}, abstract = {We present the 2.6. resolution crystal structure of a complex formed between G-actin and gelsolin fragment Met25-GIn160 (G1+). The structure differs from those of other gelsolin domain 1 (G1) complexes in that an additional six amino acid residues from the crucial linker region into gelsolin domain 2 (G2) are visible and are attached securely to the surface of actin. The linker segment extends away from G1 up the face of actin in a direction that infers G2 will bind along the same long-pitch helical strand as the actin bound to G1. This is consistent with a mechanism whereby G2 attaches gelsolin to the side of a filament and then directs G1 toward a position where it would disrupt actin-actin contacts. Alignment of the sequence of the structurally important residues within the G1-G2 linker with those of WH2 (WASp homology domain 2) domain protein family members (e.g. WASp (Wiscott-Aldridge syndrome protein) and thymosin beta4) suggests that the opposing activities of filament assembly and disassembly may exploit a common patch on the surface of actin. (C) 2003 Published by Elsevier B.V. on behalf of the Federation of European Biochemical Societies.}, keywords = {actin, BINDING, calcium, COMPLEX, crystal structure, DIFFRACTION DATA, F-ACTIN, FILAMENT, gelsolin, IDENTIFICATION, MODEL, MOTILITY, NUCLEATION, WH2 domain}, isbn = {0014-5793}, url = {://000185583000003}, author = {Irobi, E. and Burtnick, L. D. and Urosev, D. and Narayan, K. and Robinson, R. C.} }