PDBsum entry 2j4b

Transcription

PDB id: 2j4b

Contents

Protein chains

129 a.a. *

133 a.a. *

Waters ×295

* Residue conservation analysis

PDB id:

2j4b

Name:

Transcription

Title:

Crystal structure of encephalitozoon cuniculi taf5 n-terminal domain

Structure:

Transcription initiation factor tfiid subunit 72/90-100 kda. Chain: a, b, c, d, e. Fragment: n-terminal domain, residues 16-149. Synonym: taf5. Engineered: yes

Source:

Encephalitozoon cuniculi. Organism_taxid: 6035. Expressed in: escherichia coli. Expression_system_taxid: 469008.

Resolution:

2.50Å R-factor: 0.218 R-free: 0.283

Authors:

C.Romier,N.James,C.Birck,J.Cavarelli,C.Vivares,M.A.Collart,D.Moras

Key ref:

C.Romier et al. (2007). Crystal structure, biochemical and genetic characterization of yeast and E. cuniculi TAF(II)5 N-terminal domain: implications for TFIID assembly. J Mol Biol, 368, 1292-1306. PubMed id: 17397863 DOI: 10.1016/j.jmb.2007.02.039

Date:

28-Aug-06 Release date: 10-Apr-07

Protein chains

Q8SQS4  (TAF5_ENCCU) -  Transcription initiation factor TFIID subunit 5 from Encephalitozoon cuniculi (strain GB-M1)

Seq: 556 a.a.

Struc: 129 a.a.

Protein chains

Q8SQS4  (TAF5_ENCCU) -  Transcription initiation factor TFIID subunit 5 from Encephalitozoon cuniculi (strain GB-M1)

Seq: 556 a.a.

Struc: 133 a.a.

Enzyme reactions

• Enzyme class: Chains A, B, C, D, E: E.C.?

DOI no: 10.1016/j.jmb.2007.02.039

J Mol Biol 368:1292-1306 (2007)

PubMed id: 17397863

Crystal structure, biochemical and genetic characterization of yeast and E. cuniculi TAF(II)5 N-terminal domain: implications for TFIID assembly.

C.Romier, N.James, C.Birck, J.Cavarelli, C.Vivarès, M.A.Collart, D.Moras.

ABSTRACT

General transcription factor TFIID plays an essential role in transcription initiation by RNA polymerase II at numerous promoters. However, understanding of the assembly and a full structural characterization of this large 15 subunit complex is lacking. TFIID subunit TAF(II)5 has been shown to be present twice in this complex and to be critical for the function and assembly of TFIID. Especially, the TAF(II)5 N-terminal domain is required for its incorporation within TFIID and immuno-labelling experiments carried out by electron microscopy at low resolution have suggested that this domain might homodimerize, possibly explaining the three-lobed architecture of TFIID. However, the resolution at which the electron microscopy (EM) analyses were conducted is not sufficient to determine whether homodimerization occurs or whether a more intricate assembly implying other subunits is required. Here we report the X-ray structures of the fully evolutionary conserved C-terminal sub-domain of the TAF(II)5 N terminus, from yeast and the mammalian parasite Encephalitozoon cuniculi. This sub-domain displays a novel fold with specific surfaces having conserved physico-chemical properties that can form protein-protein interactions. Although a crystallographic dimer implying one of these surfaces is present in one of the crystal forms, several biochemical analyses show that this sub-domain is monomeric in solution, even at various salt conditions and in presence of different divalent cations. Consequently, the N-terminal sub-domain of the TAF(II)5 N terminus, which is homologous to a dimerization motif but has not been fully conserved during evolution, was studied by analytical ultracentrifugation and yeast genetics. Our results show that this sub-domain dimerizes at very high concentration but is neither required for yeast viability, nor for incorporation of two TAF(II)5 molecules within TFIID and for the assembly of this complex. Altogether, although our results do not argue in favour of a homodimerization of the TAF(II)5 N-terminal domain, our structural analyses suggest a role for this domain in assembly of TFIID and its related complexes SAGA, STAGA, TFTC and PCAF.

Selected figure(s)

Figure 1.

Figure 3.
Figure 3. (a) Electrostatic potential at the surface of S. cerevisiae T5N2 sub-domain. The orientation is the same as in Figure 2(c). The electrostatic potentials −8 and +8 k[B]T (k[B], Boltzmann constant; T, temperature) are coloured red and blue, respectively. The position of the four-helix bundle/linker region and triangular structure are indicated by circles. (b) Homodimer formed through the triangular structure within E. cuniculi crystals.

The above figures are reprinted by permission from Elsevier: J Mol Biol (2007, 368, 1292-1306) copyright 2007.

Figures were selected by an automated process.