1ltg: Difference between revisions

Revision as of 22:10, 2 July 2008

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File:1ltg.png

Template:STRUCTURE 1ltg

THE ARG7LYS MUTANT OF HEAT-LABILE ENTEROTOXIN EXHIBITS GREAT FLEXIBILITY OF ACTIVE SITE LOOP 47-56 OF THE A SUBUNITTHE ARG7LYS MUTANT OF HEAT-LABILE ENTEROTOXIN EXHIBITS GREAT FLEXIBILITY OF ACTIVE SITE LOOP 47-56 OF THE A SUBUNIT

Template:ABSTRACT PUBMED 7669757

About this StructureAbout this Structure

1LTG is a Protein complex structure of sequences from Escherichia coli. Full crystallographic information is available from OCA.

ReferenceReference

The Arg7Lys mutant of heat-labile enterotoxin exhibits great flexibility of active site loop 47-56 of the A subunit., van den Akker F, Merritt EA, Pizza M, Domenighini M, Rappuoli R, Hol WG, Biochemistry. 1995 Sep 5;34(35):10996-1004. PMID:7669757

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

OCA

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-[[Image:1ltg.gif|left|200px]]
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-'''THE ARG7LYS MUTANT OF HEAT-LABILE ENTEROTOXIN EXHIBITS GREAT FLEXIBILITY OF ACTIVE SITE LOOP 47-56 OF THE A SUBUNIT'''
+===THE ARG7LYS MUTANT OF HEAT-LABILE ENTEROTOXIN EXHIBITS GREAT FLEXIBILITY OF ACTIVE SITE LOOP 47-56 OF THE A SUBUNIT===
-==Overview==
+<!--
-The heat-labile enterotoxin from Escherichia coli (LT) is a member of the cholera toxin family. These and other members of the larger class of AB5 bacterial toxins act through catalyzing the ADP-ribosylation of various intracellular targets including Gs alpha. The A subunit is responsible for this covalent modification, while the B pentamer is involved in receptor recognition. We report here the crystal structure of an inactive single-site mutant of LT in which arginine 7 of the A subunit has been replaced by a lysine residue. The final model contains 103 residues for each of the five B subunits, 175 residues for the A1 subunit, and 41 residues for the A2 subunit. In this Arg7Lys structure the active site cleft within the A subunit is wider by approximately 1 A than is seen in the wild-type LT. Furthermore, a loop near the active site consisting of residues 47-56 is disordered in the Arg7Lys structure, even though the new lysine residue at position 7 assumes a position which virtually coincides with that of Arg7 in the wild-type structure. The displacement of residues 47-56 as seen in the mutant structure is proposed to be necessary for allowing NAD access to the active site of the wild-type LT. On the basis of the differences observed between the wild-type and Arg7Lys structures, we propose a model for a coordinated sequence of conformational changes required for full activation of LT upon reduction of disulfide bridge 187-199 and cleavage of the peptide loop between the two cysteines in the A subunit.(ABSTRACT TRUNCATED AT 250 WORDS)
+The line below this paragraph, {{ABSTRACT_PUBMED_7669757}}, adds the Publication Abstract to the page
+(as it appears on PubMed at http://www.pubmed.gov), where 7669757 is the PubMed ID number.
+-->
+{{ABSTRACT_PUBMED_7669757}}
 ==About this Structure==
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 [[Category: Hol, W G.J.]]
 [[Category: Enterotoxin]]
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