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1exe
From Proteopedia
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SOLUTION STRUCTURE OF A MUTANT OF TRANSCRIPTION FACTOR 1.
Overview
An NMR solution structure of a mutant of the homodimer protein, transcription factor 1, TF1-G15/I32 (22 kDa), has been solved to atomic, resolution, with 23 final structures that converge to an r.m. s.d. of 0.78, A. The overall shape of TF1-G15/I32 remains similar to that of the, wild-type protein and other type II DNA-binding proteins. Each monomer has, two N-terminal alpha-helices separated by a short loop, followed by a, three-stranded beta-sheet, whose extension between the second and third, beta-strands forms an antiparallel beta-ribbon arm, leading to a, C-terminal third alpha-helix that is severely kinked in the middle. Close, examination of the structure of TF1-G15/I32 reveals why it is more stable, and binds DNA more tightly than does its wild-type counterpart. The, dimeric core, consisting of the N-terminal helices and the beta-sheets, is, more tightly packed, and this might be responsible for its increased, thermal stability. The DNA-binding domain, composed of the top face of the, beta-sheet, the beta-ribbon arms and the C-terminal helices, is little, changed from wild-type TF1. Rather, the enhancement in DNA affinity must, be due almost exclusively to the creation of an additional DNA-binding, site at the side of the dimer by changes affecting helices 1 and 2: helix, 2 of TF1-G15/I32 is one residue longer than helix 2 of the wild-type, protein, bends inward, and is both translationally and rotationally, displaced relative to helix 1. This rearrangement creates a longer, narrower fissure between the V-shaped N-terminal helices and exposes, additional positively charged surface at each side of the dimer.
About this Structure
1EXE is a Single protein structure of sequence from Vigna unguiculata subsp. cylindrica. Full crystallographic information is available from OCA.
Reference
Solution structure of a mutant of transcription factor 1: implications for enhanced DNA binding., Liu W, Vu HM, Geiduschek EP, Kearns DR, J Mol Biol. 2000 Sep 29;302(4):821-30. PMID:10993726
Page seeded by OCA on Tue Nov 20 14:24:02 2007
