PDBsum entry 1txe

Transport protein

PDB id: 1txe

Contents

Protein chain

88 a.a. *

* Residue conservation analysis

PDB id:

1txe

Name:

Transport protein

Title:

Solution structure of the active-centre mutant ile14ala of the histidine-containing phosphocarrier protein (hpr) from staphylococcus carnosus

Structure:

Phosphocarrier protein hpr. Chain: a. Synonym: histidine-containing protein. Engineered: yes. Mutation: yes

Source:

Staphylococcus carnosus. Organism_taxid: 1281. Expressed in: escherichia coli bl21(de3). Expression_system_taxid: 469008.

NMR struc:

10 models

Authors:

A.Moeglich,B.Koch,W.Hengstenberg,E.Brunner,H.R.Kalbitzer,Structural Proteomics In Europe (Spine)

Key ref:

A.Möglich et al. (2004). Solution structure of the active-centre mutant I14A of the histidine-containing phosphocarrier protein from Staphylococcus carnosus. Eur J Biochem, 271, 4815-4824. PubMed id: 15606769 DOI: 10.1111/j.1432-1033.2004.04447.x

Date:

04-Jul-04 Release date: 08-Mar-05

Protein chain

P23534  (PTHP_STACA) -  Phosphocarrier protein HPr from Staphylococcus carnosus

Seq: 88 a.a.

Struc: 88 a.a.*

* PDB and UniProt seqs differ at 1 residue position (black cross)

Enzyme reactions

• Enzyme class: E.C.?

DOI no: 10.1111/j.1432-1033.2004.04447.x

Eur J Biochem 271:4815-4824 (2004)

PubMed id: 15606769

Solution structure of the active-centre mutant I14A of the histidine-containing phosphocarrier protein from Staphylococcus carnosus.

A.Möglich, B.Koch, W.Gronwald, W.Hengstenberg, E.Brunner, H.R.Kalbitzer.

ABSTRACT

High-pressure NMR experiments performed on the histidine-containing phosphocarrier protein (HPr) from Staphylococcus carnosus have shown that residue Ile14, which is located in the active-centre loop, exhibits a peculiarly small pressure response. In contrast, the rest of the loop shows strong pressure effects as is expected for typical protein interaction sites. To elucidate the structural role of this residue, the mutant protein HPr(I14A), in which Ile14 is replaced by Ala, was produced and studied by solution NMR spectroscopy. On the basis of 1406 structural restraints including 20 directly detected hydrogen bonds, 49 1H(N)-15N, and 25 1H(N)-1Halpha residual dipolar couplings, a well resolved three-dimensional structure could be determined. The overall fold of the protein is not influenced by the mutation but characteristic conformational changes are introduced into the active-centre loop. They lead to a displacement of the ring system of His15 and a distortion of the N-terminus of the first helix, which supports the histidine ring. In addition, the C-terminal helix is bent because the side chain of Leu86 located at the end of this helix partly fills the hydrophobic cavity created by the mutation. Xenon, which is known to occupy hydrophobic cavities, causes a partial reversal of the mutation-induced structural effects. The observed structural changes explain the reduced phosphocarrier activity of the mutant and agree well with the earlier suggestion that Ile14 represents an anchoring point stabilizing the active-centre loop in its correct conformation.

Selected figure(s)

Figure 4.
Fig. 4. Comparison of wild-type and mutant HPr. Comparison of the three-dimensional structures of the mutant (left) and wild-type HPr (right). The side chains of the catalytically active histidine residue 15 and of residue 14 (isoleucine to alanine) are shown in blue and yellow, respectively. Residues Ala19 and Leu86 are indicated in red. The removal of the isoleucine side chain in the mutant protein leads to significant structural rearrangements (see text).

Figure 6.
Fig. 6. Hydrophobic cavity of HPr(I14A). The solvent-accessible surface of the HPr(I14A) molecule is shown. Residues 14, 15, 19 and 86 are coloured as in Fig. 4. A cavity in the region where the mutation has been introduced is marked by the arrows. The existence of this cavity was confirmed by xenon-binding studies.

The above figures are reprinted by permission from the Federation of European Biochemical Societies: Eur J Biochem (2004, 271, 4815-4824) copyright 2004.

Figures were selected by an automated process.