PDBsum entry 3lhs

Transport protein

PDB id: 3lhs

Contents

Protein chain

291 a.a. *

Ligands

GOL ×3

SF8

Metals

_FE

Waters ×313

* Residue conservation analysis

PDB id:

3lhs

Name:

Transport protein

Title:

Open conformation of htsa complexed with staphyloferrin a

Structure:

Ferrichrome abc transporter lipoprotein. Chain: a. Fragment: unp residues 38-327. Engineered: yes

Source:

Staphylococcus aureus subsp. Aureus strain. Organism_taxid: 426430. Strain: newman. Gene: htsa, nwmn_2078. Expressed in: escherichia coli. Expression_system_taxid: 562.

Resolution:

1.30Å R-factor: 0.155 R-free: 0.186

Authors:

J.C.Grigg,M.E.P.Murphy

Key ref:

J.C.Grigg et al. (2010). The Staphylococcus aureus siderophore receptor HtsA undergoes localized conformational changes to enclose staphyloferrin A in an arginine-rich binding pocket. J Biol Chem, 285, 11162-11171. PubMed id: 20147287

Date:

23-Jan-10 Release date: 09-Feb-10

Protein chain

A0A0H3K9U6  (A0A0H3K9U6_STAAE) -  ABC transporter substrate-binding protein from Staphylococcus aureus (strain Newman)

Seq: 327 a.a.

Struc: 291 a.a.*

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

Enzyme reactions

• Enzyme class: E.C.?

J Biol Chem 285:11162-11171 (2010)

PubMed id: 20147287

The Staphylococcus aureus siderophore receptor HtsA undergoes localized conformational changes to enclose staphyloferrin A in an arginine-rich binding pocket.

J.C.Grigg, J.D.Cooper, J.Cheung, D.E.Heinrichs, M.E.Murphy.

ABSTRACT

Staphylococcus aureus uses several efficient iron acquisition strategies to overcome iron limitation. Recently, the genetic locus encoding biosynthetic enzymes for the iron chelating molecule, staphyloferrin A (SA), was determined. S. aureus synthesizes and secretes SA into its environment to scavenge iron. The membrane-anchored ATP binding cassette-binding protein, HtsA, receives the ferric-chelate for import into the cell. Recently, we determined the apoHtsA crystal structure, the first siderophore receptor from gram-positive bacteria to be structurally characterized. Herein we present the x-ray crystal structure of the HtsA-ferric-SA complex. HtsA adopts a class III binding protein fold composed of separate N- and C-terminal domains bridged by a single alpha-helix. Recombinant HtsA can efficiently sequester ferric-SA from S. aureus culture supernatants where it is bound within the pocket formed between distinct N- and C-terminal domains. A basic patch composed mainly of six Arg residues contact the negatively charged siderophore, securing it within the pocket. The x-ray crystal structures from two different ligand-bound crystal forms were determined. The structures represent the first structural characterization of an endogenous alpha-hydroxycarboxylate-type siderophore-receptor complex. One structure is in an open form similar to apoHtsA, whereas the other is in a more closed conformation. The conformational change is highlighted by isolated movement of three loops within the C-terminal domain, a domain movement unique to known class III binding protein structures.