2a6x: Difference between revisions

Revision as of 18:41, 3 May 2008

Crystal structure of Emp46p carbohydrate recognition domain (CRD), Y131F mutant

OverviewOverview

Emp46p and Emp47p are type I membrane proteins, which cycle between the endoplasmic reticulum (ER) and the Golgi apparatus by vesicles coated with coat protein complexes I and II (COPI and COPII). They are considered to function as cargo receptors for exporting N-linked glycoproteins from the ER. We have determined crystal structures of the carbohydrate recognition domains (CRDs) of Emp46p and Emp47p of Saccharomyces cerevisiae, in the absence and presence of metal ions. Both proteins fold as a beta-sandwich, and resemble that of the mammalian ortholog, p58/ERGIC-53. However, the nature of metal binding is distinct from that of Ca(2+)-dependent p58/ERGIC-53. Interestingly, the CRD of Emp46p does not bind Ca(2+) ion but instead binds K(+) ion at the edge of a concave beta-sheet whose position is distinct from the corresponding site of the Ca(2+) ion in p58/ERGIC-53. Binding of K(+) ion to Emp46p appears essential for transport of a subset of glycoproteins because the Y131F mutant of Emp46p, which cannot bind K(+) ion fails to rescue the transport in disruptants of EMP46 and EMP47 genes. In contrast the CRD of Emp47p binds no metal ions at all. Furthermore, the CRD of Emp46p binds to glycoproteins carrying high mannosetype glycans and the is promoted by binding not the addition of Ca(2+) or K(+) ion in These results suggest that Emp46p can be regarded as a Ca(2+)-independent intracellular lectin at the ER exit sites.

About this StructureAbout this Structure

2A6X is a Single protein structure of sequence from Saccharomyces cerevisiae. Full crystallographic information is available from OCA.

ReferenceReference

Structures of the carbohydrate recognition domain of Ca2+-independent cargo receptors Emp46p and Emp47p., Satoh T, Sato K, Kanoh A, Yamashita K, Yamada Y, Igarashi N, Kato R, Nakano A, Wakatsuki S, J Biol Chem. 2006 Apr 14;281(15):10410-9. Epub 2006 Jan 26. PMID:16439369 Page seeded by OCA on Sat May 3 18:41:02 2008

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OCA

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 '''Crystal structure of Emp46p carbohydrate recognition domain (CRD), Y131F mutant'''
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 [[Category: Wakatsuki, S.]]
 [[Category: Yamashita, K.]]
-[[Category: beta sandwich]]
+[[Category: Beta sandwich]]
-[[Category: carbohydrate binding protein]]
+[[Category: Carbohydrate binding protein]]
-[[Category: cargo receptor]]
+[[Category: Cargo receptor]]
-[[Category: national project on protein structural and functional analyse]]
+[[Category: National project on protein structural and functional analyse]]
-[[Category: nppsfa]]
+[[Category: Nppsfa]]
-[[Category: riken structural genomics/proteomics initiative]]
+[[Category: Riken structural genomics/proteomics initiative]]
-[[Category: rsgi]]
+[[Category: Rsgi]]
-[[Category: structural genomic]]
+[[Category: Structural genomic]]
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May  3 18:41:02 2008''
-''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Mar 31 01:48:38 2008''