2in8

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spinqualitylabelsall models 2in8, resolution 1.70Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

crystal structure of Mtu recA intein, splicing domain

Overview

The 440 amino acid Mtu recA intein consists of independent, protein-splicing and endonuclease domains. Previously, removal of the, central endonuclease domain of the intein, and selection for function, generated a 168 residue mini-intein, DeltaI-SM, that had splicing activity, similar to that of the full-length, wild-type protein. A D422G mutation, (DeltaI-CM) increased C-terminal cleavage activity. Using the DeltaI-SM, mini-intein structure (presented here) as a guide, we previously generated, a highly active 139 residue mini-intein, DeltaDeltaI(hh)-SM, by replacing, 36 amino acid residues in the residual endonuclease loop with a, seven-residue beta-turn from the autoprocessing domain of Hedgehog, protein. The three-dimensional structures of DeltaI-SM, DeltaDeltaI(hh)-SM, and two variants, DeltaDeltaI(hh)-CM and, DeltaDeltaI(hh), have been determined to evaluate the effects of the, minimization on intein integrity and to investigate the structural and, functional consequences of the D422G mutation. These structural studies, show that Asp422 is capable of interacting with both the N and C termini., These interactions are lacking in the CM variant, but are replaced by, contacts with water molecules. Accordingly, additional mutagenesis of, residue 422, combined with mutations that isolate N-terminal and, C-terminal cleavage, showed that the side-chain of Asp422 plays a role in, both N and C-terminal cleavage, thereby suggesting that this highly, conserved residue regulates the balance between the two reactions.

About this Structure

2IN8 is a Single protein structure of sequence from Mycobacterium tuberculosis with as ligand. Full crystallographic information is available from OCA.

Reference

Crystallographic and mutational studies of Mycobacterium tuberculosis recA mini-inteins suggest a pivotal role for a highly conserved aspartate residue., Van Roey P, Pereira B, Li Z, Hiraga K, Belfort M, Derbyshire V, J Mol Biol. 2007 Mar 16;367(1):162-73. Epub 2006 Dec 23. PMID:17254599

Page seeded by OCA on Wed Jan 23 15:27:42 2008