Linked Life Data

14752117

Source:http://linkedlifedata.com/resource/pubmed/id/14752117

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
17
pubmed:dateCreated
2004-4-19
pubmed:databankReference
pubmed:abstractText
Kre2p/Mnt1p is a Golgi alpha1,2-mannosyltransferase involved in the biosynthesis of Saccharomyces cerevisiae cell wall glycoproteins. The protein belongs to glycosyltransferase family 15, a member of which has been implicated in virulence of Candida albicans. We present the 2.0 A crystal structures of the catalytic domain of Kre2p/Mnt1p and its binary and ternary complexes with GDP/Mn(2+) and GDP/Mn(2+)/acceptor methyl-alpha-mannoside. The protein has a mixed alpha/beta fold similar to the glycosyltransferase-A (GT-A) fold. Although the GDP-mannose donor was used in the crystallization experiments and the GDP moiety is bound tightly to the active site, the mannose is not visible in the electron density. The manganese is coordinated by a modified DXD motif (EPD), with only the first glutamate involved in a direct interaction. The position of the donor mannose was modeled using the binary and ternary complexes of other GT-A enzymes. The C1" of the modeled donor mannose is within hydrogen-bonding distance of both the hydroxyl of Tyr(220) and the O2 of the acceptor mannose. The O2 of the acceptor mannose is also within hydrogen bond distance of the hydroxyl of Tyr(220). The structures, modeling, site-directed mutagenesis, and kinetic analysis suggest two possible catalytic mechanisms. Either a double-displacement mechanism with the hydroxyl of Tyr(220) as the potential nucleophile or alternatively, an S(N)i-like mechanism with Tyr(220) positioning the substrates for catalysis. The importance of Tyr(220) in both mechanisms is highlighted by a 3000-fold reduction in k(cat) in the Y220F mutant.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
23
pubmed:volume
279
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
17921-31
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed-meshheading:14752117-Binding Sites, pubmed-meshheading:14752117-Catalysis, pubmed-meshheading:14752117-Catalytic Domain, pubmed-meshheading:14752117-Cell Wall, pubmed-meshheading:14752117-Circular Dichroism, pubmed-meshheading:14752117-Crystallography, X-Ray, pubmed-meshheading:14752117-Electrons, pubmed-meshheading:14752117-Glycoproteins, pubmed-meshheading:14752117-Guanosine Diphosphate, pubmed-meshheading:14752117-Hydrogen Bonding, pubmed-meshheading:14752117-Kinetics, pubmed-meshheading:14752117-Mannose, pubmed-meshheading:14752117-Mannosyltransferases, pubmed-meshheading:14752117-Membrane Glycoproteins, pubmed-meshheading:14752117-Models, Chemical, pubmed-meshheading:14752117-Models, Molecular, pubmed-meshheading:14752117-Mutagenesis, Site-Directed, pubmed-meshheading:14752117-Mutation, pubmed-meshheading:14752117-Oxygen, pubmed-meshheading:14752117-Pichia, pubmed-meshheading:14752117-Plasmids, pubmed-meshheading:14752117-Protein Folding, pubmed-meshheading:14752117-Protein Structure, Tertiary, pubmed-meshheading:14752117-Saccharomyces cerevisiae Proteins, pubmed-meshheading:14752117-Tyrosine
pubmed:year
2004
pubmed:articleTitle
Structure of Kre2p/Mnt1p: a yeast alpha1,2-mannosyltransferase involved in mannoprotein biosynthesis.
pubmed:affiliation
Program in Structural Biology and Biochemistry, Research Institute, The Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.