PDBsum entry: 1exe

Transcription

PDB id: 1exe

Contents

Protein chains

99 a.a. *

* Residue conservation analysis

PDB id:

1exe

Name:

Transcription

Title:

Solution structure of a mutant of transcription factor 1.

Structure:

Transcription factor 1. Chain: a, b. Engineered: yes. Mutation: yes

Source:

Bacillus phage spo1. Organism_taxid: 10685. Expressed in: escherichia coli. Expression_system_taxid: 562.

NMR struc:

23 models

Authors:

W.Liu,H.M.Vu,E.P.Geiduschek,D.R.Kearns

Key ref:

W.Liu et al. (2000). Solution structure of a mutant of transcription factor 1: implications for enhanced DNA binding. J Mol Biol, 302, 821-830. PubMed id: 10993726 DOI: 10.1006/jmbi.2000.4084

Date:

02-May-00 Release date: 18-Oct-00

Protein chains

P04445  (TF1_BPSP1) -  Transcription factor 1

Seq: 99 a.a.

Struc: 99 a.a.*

* PDB and UniProt seqs differ at 2 residue positions (black crosses)

 Gene Ontology (GO) functional annotation 

• Biological process: regulation of transcription (2 terms)
• Biochemical function: DNA binding (1 term)

DOI no: 10.1006/jmbi.2000.4084

J Mol Biol 302:821-830 (2000)

PubMed id: 10993726

Solution structure of a mutant of transcription factor 1: implications for enhanced DNA binding.

W.Liu, H.M.Vu, E.P.Geiduschek, D.R.Kearns.

ABSTRACT

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.

Selected figure(s)

Figure 1.
Figure 1. An average structure of TF1-G15/I32. Helices (H) are shown in red, loops in yellow, b-strands (B) in blue, and b-ribbon arm in green. The second monomer is shown dimly in gray. H1=residues 1-13, H2=20-40, H3=83-99, B1=41-44, B2=48-51, B3= 78-82, and b-ribbon ARM=52-77.

Figure 5.
Figure 5. The N-terminal helices of TF1 (blue) and TF1-G15/I32 (pink) superimposed on each other. The side-chains of residues 15 and 32 are also shown. Broken lines indicate distances from the alpha carbon atoms of Lys3 to Leu25 of wild-type TF1 (7.4 Å) and TF1-G15/I32 (5.7 Å), and from the alpha carbon atoms of Lys3 to Leu16 of TF1 (14.8 Å) and TF1-G15/I32 (18.5 Å).

The above figures are reprinted by permission from Elsevier: J Mol Biol (2000, 302, 821-830) copyright 2000.

Figures were selected by an automated process.