1bw5
From Proteopedia
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THE NMR SOLUTION STRUCTURE OF THE HOMEODOMAIN OF THE RAT INSULIN GENE ENHANCER PROTEIN ISL-1, 50 STRUCTURES
Overview
Homeodomains are one of the key families of eukaryotic DNA-binding motifs, and provide an important model system for DNA recognition. We have, determined a high-quality nuclear magnetic resonance (NMR) structure of, the DNA-binding homeodomain of the insulin gene enhancer protein Isl-1, (Isl-1-HD). It forms the first solution structure of a homeodomain from, the LIM family. It contains a well-defined inner core (residues 12-55), consisting of the classical three-helix structure observed in other, homeodomains. The N terminus is unstructured up to residue 8, while the C, terminus gradually becomes unstructured from residue 55 onwards. Some, flexibility is evident in the loop parts of the inner core. Isl-1-HD has, despite its low sequence identity (23-34 %), a structure that is, strikingly similar to that of the other homeodomains with known, three-dimensional structures. Detailed analysis of Isl-1-HD and the other, homeodomains rationalizes the differences in their temperature stability, and explains the low stability of the Isl-1-HD in the free state (tm 22-30, degrees C). Upon DNA binding, a significant stabilization occurs (tm>55, degrees C). The low stability of Isl-1-HD (and other mammalian, homeodomains) suggests that in vivo Isl-1-HD recognizes its cognate DNA, from its unfolded state.
About this Structure
1BW5 is a Single protein structure of sequence from Rattus norvegicus. Full crystallographic information is available from OCA.
Reference
The solution structure of the homeodomain of the rat insulin-gene enhancer protein isl-1. Comparison with other homeodomains., Ippel H, Larsson G, Behravan G, Zdunek J, Lundqvist M, Schleucher J, Lycksell PO, Wijmenga S, J Mol Biol. 1999 May 14;288(4):689-703. PMID:10329173
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