1s4o: Difference between revisions

Revision as of 08:17, 3 May 2008

Crystal structure of yeast alpha1,2-mannosyltransferase Kre2p/Mnt1p: binary complex with GDP/Mn

OverviewOverview

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.

About this StructureAbout this Structure

1S4O is a Single protein structure of sequence from Saccharomyces cerevisiae. Full crystallographic information is available from OCA.

ReferenceReference

Structure of Kre2p/Mnt1p: a yeast alpha1,2-mannosyltransferase involved in mannoprotein biosynthesis., Lobsanov YD, Romero PA, Sleno B, Yu B, Yip P, Herscovics A, Howell PL, J Biol Chem. 2004 Apr 23;279(17):17921-31. Epub 2004 Jan 28. PMID:14752117 Page seeded by OCA on Sat May 3 08:17:34 2008

Proteopedia Page Contributors and Editors (what is this?)Proteopedia Page Contributors and Editors (what is this?)

OCA

@@ Line 1: / Line 1: @@
 [[Image:1s4o.gif|left|200px]]
- {{Structure
+<!--
-|PDB= 1s4o |SIZE=350|CAPTION= <scene name='initialview01'>1s4o</scene>, resolution 2.01&Aring;
+The line below this paragraph, containing "STRUCTURE_1s4o", creates the "Structure Box" on the page.
-|SITE=
+You may change the PDB parameter (which sets the PDB file loaded into the applet)
-|LIGAND= <scene name='pdbligand=BMA:BETA-D-MANNOSE'>BMA</scene>, <scene name='pdbligand=CL:CHLORIDE+ION'>CL</scene>, <scene name='pdbligand=EPE:4-(2-HYDROXYETHYL)-1-PIPERAZINE+ETHANESULFONIC+ACID'>EPE</scene>, <scene name='pdbligand=GDP:GUANOSINE-5&#39;-DIPHOSPHATE'>GDP</scene>, <scene name='pdbligand=MAN:ALPHA-D-MANNOSE'>MAN</scene>, <scene name='pdbligand=MN:MANGANESE+(II)+ION'>MN</scene>, <scene name='pdbligand=NAG:N-ACETYL-D-GLUCOSAMINE'>NAG</scene>, <scene name='pdbligand=NDG:2-(ACETYLAMINO)-2-DEOXY-A-D-GLUCOPYRANOSE'>NDG</scene>
+or the SCENE parameter (which sets the initial scene displayed when the page is loaded),
-|ACTIVITY= <span class='plainlinks'>[http://en.wikipedia.org/wiki/Glycolipid_2-alpha-mannosyltransferase Glycolipid 2-alpha-mannosyltransferase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.4.1.131 2.4.1.131] </span>
+or leave the SCENE parameter empty for the default display.
-|GENE= KRE2, MNT1, YDR483W, D8035.26 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=4932 Saccharomyces cerevisiae])
+-->
-|DOMAIN=
+{{STRUCTURE_1s4o|  PDB=1s4o  |  SCENE=  }}
-|RELATEDENTRY=
-|RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1s4o FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1s4o OCA], [http://www.ebi.ac.uk/pdbsum/1s4o PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=1s4o RCSB]</span>
-}}
 '''Crystal structure of yeast alpha1,2-mannosyltransferase Kre2p/Mnt1p: binary complex with GDP/Mn'''
@@ Line 33: / Line 30: @@
 [[Category: Yip, P.]]
 [[Category: Yu, B.]]
-[[Category: alpha/beta fold]]
+[[Category: Alpha/beta fold]]
-[[Category: binary complex with gdp/mn2+]]
+[[Category: Binary complex with gdp/mn2+]]
-[[Category: nucleotide-binding domain]]
+[[Category: Nucleotide-binding domain]]
-[[Category: rossmann fold]]
+[[Category: Rossmann fold]]
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May  3 08:17:34 2008''
-''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Mar 30 23:37:22 2008''