1cgw: Difference between revisions

Revision as of 20:44, 30 June 2008

This article has been automatically seeded. Changes to this page should pertain to the PDB entry only and not to the protein or biomolecule in general.

File:1cgw.png

Template:STRUCTURE 1cgw

SITE DIRECTED MUTATIONS OF THE ACTIVE SITE RESIDUE TYROSINE 195 OF CYCLODEXTRIN GLYCOSYLTRANSFERASE FROM BACILLUS CIRCULANS STRAIN 251 AFFECTING ACTIVITY AND PRODUCT SPECIFICITYSITE DIRECTED MUTATIONS OF THE ACTIVE SITE RESIDUE TYROSINE 195 OF CYCLODEXTRIN GLYCOSYLTRANSFERASE FROM BACILLUS CIRCULANS STRAIN 251 AFFECTING ACTIVITY AND PRODUCT SPECIFICITY

Template:ABSTRACT PUBMED 7880832

About this StructureAbout this Structure

1CGW is a Single protein structure of sequence from Bacillus circulans. Full crystallographic information is available from OCA.

ReferenceReference

Site-directed mutations in tyrosine 195 of cyclodextrin glycosyltransferase from Bacillus circulans strain 251 affect activity and product specificity., Penninga D, Strokopytov B, Rozeboom HJ, Lawson CL, Dijkstra BW, Bergsma J, Dijkhuizen L, Biochemistry. 1995 Mar 14;34(10):3368-76. PMID:7880832

Page seeded by OCA on Mon Jun 30 20:44:01 2008

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

OCA

@@ Line 1: / Line 1: @@
-[[Image:1cgw.jpg|left|200px]]
+{{Seed}}
+[[Image:1cgw.png|left|200px]]
 <!--
@@ Line 9: / Line 10: @@
 {{STRUCTURE_1cgw|  PDB=1cgw  |  SCENE=  }}
-'''SITE DIRECTED MUTATIONS OF THE ACTIVE SITE RESIDUE TYROSINE 195 OF CYCLODEXTRIN GLYCOSYLTRANSFERASE FROM BACILLUS CIRCULANS STRAIN 251 AFFECTING ACTIVITY AND PRODUCT SPECIFICITY'''
+===SITE DIRECTED MUTATIONS OF THE ACTIVE SITE RESIDUE TYROSINE 195 OF CYCLODEXTRIN GLYCOSYLTRANSFERASE FROM BACILLUS CIRCULANS STRAIN 251 AFFECTING ACTIVITY AND PRODUCT SPECIFICITY===
-==Overview==
+<!--
-Tyrosine 195 is located in the center of the active site cleft of cyclodextrin glycosyltransferase (EC 2.4.1.19) from Bacillus circulans strain 251. Alignment of amino acid sequences of CGTases and alpha-amylases, and the analysis of the binding mode of the substrate analogue acarbose in the active site cleft [Strokopytov, B., et al. (1995) Biochemistry 34, (in press)], suggested that Tyr195 plays an important role in cyclization of oligosaccharides. Tyr195 therefore was replaced with Phe (Y195F), Trp (Y195W), Leu (Y195L), and Gly (Y195G). Mutant proteins were purified and crystallized, and their X-ray structures were determined at 2.5-2.6 angstrum resolution, allowing a detailed comparison of their biochemical properties and three-dimensional structures with those of the wild-type CGTase protein. The mutant proteins possessed significantly reduced cyclodextrin forming and coupling activities but were not negatively affected in the disproportionation and saccharifying reactions. Also under production process conditions, after a 45 h incubation with a 10% starch solution, the Y195W, Y195L, and Y195G mutants showed a lower overall conversion of starch into cyclodextrins. These mutants produced a considerable amount of linear maltooligosaccharides. The presence of aromatic amino acids (Tyr or Phe) at the Tyr195 position thus appears to be of crucial importance for an efficient cyclization reaction, virtually preventing the formation of linear products. Mass spectrometry of the Y195L reaction mixture, but not that of the other mutants and the wild type, revealed a shift toward the synthesis (in low yields) of larger products, especially of beta- and gamma- (but no alpha-) cyclodextrins and minor amounts of delta-, epsilon-, zeta- and eta-cyclodextrins.(ABSTRACT TRUNCATED AT 250 WORDS)
+The line below this paragraph, {{ABSTRACT_PUBMED_7880832}}, adds the Publication Abstract to the page
+(as it appears on PubMed at http://www.pubmed.gov), where 7880832 is the PubMed ID number.
+-->
+{{ABSTRACT_PUBMED_7880832}}
 ==About this Structure==
@@ Line 26: / Line 30: @@
 [[Category: Strokopytov, B V.]]
 [[Category: Glycosyltransferase]]
-''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May  2 12:43:19 2008''
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Jun 30 20:44:01 2008''