PDBsum entry 1s8l

Membrane protein

PDB id: 1s8l

Contents

Protein chain

219 a.a. *

Ligands

RET

LI1 ×8

Waters ×48

* Residue conservation analysis

PDB id:

1s8l

Name:

Membrane protein

Title:

Anion-free form of the d85s mutant of bacteriorhodopsin from crystals grown in the presence of halide

Structure:

Bacteriorhodopsin precursor. Chain: a. Synonym: br. Engineered: yes. Mutation: yes

Source:

Halobacterium sp.. Organism_taxid: 2243. Gene: bop, vng1467g. Expressed in: halobacterium. Expression_system_taxid: 2239

Resolution:

2.30Å R-factor: 0.221 R-free: 0.253

Authors:

M.T.Facciotti,V.S.Cheung,C.S.Lunde,S.Rouhani,N.S.Baliga,R.M.Glaeser

Key ref:

M.T.Facciotti et al. (2004). Specificity of anion binding in the substrate pocket of bacteriorhodopsin. Biochemistry, 43, 4934-4943. PubMed id: 15109251 DOI: 10.1021/bi035757s

Date:

02-Feb-04 Release date: 08-Jun-04

Protein chain

P02945  (BACR_HALSA) -  Bacteriorhodopsin from Halobacterium salinarum (strain ATCC 700922 / JCM 11081 / NRC-1)

Seq: 262 a.a.

Struc: 219 a.a.*

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

DOI no: 10.1021/bi035757s

Biochemistry 43:4934-4943 (2004)

PubMed id: 15109251

Specificity of anion binding in the substrate pocket of bacteriorhodopsin.

M.T.Facciotti, V.S.Cheung, C.S.Lunde, S.Rouhani, N.S.Baliga, R.M.Glaeser.

ABSTRACT

The structure of the D85S mutant of bacteriorhodopsin with a nitrate anion bound in the Schiff base binding site and the structure of the anion-free protein have been obtained in the same crystal form. Together with the previously solved structures of this anion pump, in both the anion-free state and bromide-bound state, these new structures provide insight into how this mutant of bacteriorhodopsin is able to bind a variety of different anions in the same binding pocket. The structural analysis reveals that the main structural change that accommodates different anions is the repositioning of the polar side chain of S85. On the basis of these X-ray crystal structures, the prediction is then made that the D85S/D212N double mutant might bind similar anions and do so over a broader pH range than does the single mutant. Experimental comparison of the dissociation constants, K(d), for a variety of anions confirms this prediction and demonstrates, in addition, that the binding affinity is dramatically improved by the D212N substitution.