PDBsum entry 1yy7

Transcription

PDB id: 1yy7

Contents

Protein chains

206 a.a. *

Ligands

CIT ×2

Waters ×441

* Residue conservation analysis

PDB id:

1yy7

Name:

Transcription

Title:

Crystal structure of stringent starvation protein a (sspa), an RNA polymerase-associated transcription factor

Structure:

Stringent starvation protein a. Chain: a, b. Synonym: sspa. Engineered: yes

Source:

Yersinia pestis. Organism_taxid: 632. Gene: sspa. Expressed in: escherichia coli bl21. Expression_system_taxid: 511693.

Biol. unit:

Dimer (from PQS)

Resolution:

2.02Å R-factor: 0.179 R-free: 0.215

Authors:

A.-M.Hansen,Y.Gu,M.Li,M.Andrykovitch,D.S.Waugh,D.J.Jin,X.Ji

Key ref:

A.M.Hansen et al. (2005). Structural basis for the function of stringent starvation protein a as a transcription factor. J Biol Chem, 280, 17380-17391. PubMed id: 15735307 DOI: 10.1074/jbc.M501444200

Date:

23-Feb-05 Release date: 01-Mar-05

Protein chains

A0A2U2GZL1  (A0A2U2GZL1_YERPE) -  Stringent starvation protein A from Yersinia pestis

Seq: 213 a.a.

Struc: 206 a.a.

DOI no: 10.1074/jbc.M501444200

J Biol Chem 280:17380-17391 (2005)

PubMed id: 15735307

Structural basis for the function of stringent starvation protein a as a transcription factor.

A.M.Hansen, Y.Gu, M.Li, M.Andrykovitch, D.S.Waugh, D.J.Jin, X.Ji.

ABSTRACT

Stringent starvation protein A (SspA) of Escherichia coli is an RNA polymerase-associated transcriptional activator for the lytic development of phage P1 and is essential for stationary phase-induced acid tolerance of E. coli. We report the crystal structure of Yersinia pestis SspA, which is 83% identical to E. coli SspA in amino acid sequence and is functionally complementary in supporting the lytic growth of phage P1 and acid resistance of an E. coli sspA mutant. The structure reveals that SspA assumes the characteristic fold of glutathione S-transferase (GST). However, SspA lacks GST activity and does not bind glutathione. Three regions of SspA are flexible, the N and C termini and the alpha2-helix. The structure also reveals a conserved surface-exposed pocket composed of residues from a loop between helices alpha3 and alpha4. The functional roles of these structural features were investigated by assessing the ability of deletion and site-directed mutants to confer acid resistance of E. coli and to activate transcription from a phage P1 late promoter, thereby supporting the lytic growth of phage P1. The results indicate that the flexible regions are not critical for SspA function, whereas the surface pocket is important for both transcriptional activation of the phage P1 late promoter and acid resistance of E. coli. The size, shape, and property of the pocket suggest that it mediates protein-protein interactions. SspA orthologs from Y. pestis, Vibrio cholerae, and Pseudomonas aeruginosa are all functional in acid resistance of E. coli, whereas only Y. pestis SspA supports phage P1 growth.

Selected figure(s)

Figure 1.
FIG. 1. Overall structure of Y. pestis SspA. The dimeric molecule is illustrated as ribbon diagrams (helices as spirals, -strands as arrows, and loops as pipes) with the two domains of each subunit colored in cyan and orange, respectively. The figure was prepared with MOL-SCRIPT (65) and Raster3D (66).

Figure 2.
FIG. 2. Stereoviews showing structural comparisons. A, comparison between Mol A (blue) and Mol B (cyan) of Y. pestis SspA. B, comparison between Mol A of Y. pestis SspA (blue, this work) and one subunit of GST B1-1 in complex with GSH (green, PDB code 2PMT [PDB] , Ref. 55). C, comparison between Mol A of Y. pestis SspA (blue, this work) and Ure2p (red, PDB code 1G6W [PDB] , Ref. 51). The protein is illustrated as ribbon diagrams (helices as spirals, -strands as arrows, and loops as pipes). The figure was prepared with MOLSCRIPT (65).

The above figures are reprinted by permission from the ASBMB: J Biol Chem (2005, 280, 17380-17391) copyright 2005.

Figures were selected by an automated process.