PDBsum entry 1xrd

Membrane protein

PDB id: 1xrd

Contents

Protein chain

52 a.a. *

* Residue conservation analysis

PDB id:

1xrd

Name:

Membrane protein

Title:

Light-harvesting complex 1 alfa subunit from wild-type rhodospirillum rubrum

Structure:

Light-harvesting protein b-880, alpha chain. Chain: a. Synonym: lh-1. Antenna pigment protein, alpha chain

Source:

Rhodospirillum rubrum. Organism_taxid: 1085

NMR struc:

10 models

Authors:

Z.-Y.Wang,K.Gokan,M.Kobayashi,T.Nozawa

Key ref:

Z.Y.Wang et al. (2005). Solution structures of the core light-harvesting alpha and beta polypeptides from Rhodospirillum rubrum: implications for the pigment-protein and protein-protein interactions. J Mol Biol, 347, 465-477. PubMed id: 15740753 DOI: 10.1016/j.jmb.2005.01.017

Date:

14-Oct-04 Release date: 15-Mar-05

Protein chain

P02947  (LHA_RHORU) -  Light-harvesting protein B-870 alpha chain from Rhodospirillum rubrum

Seq: 62 a.a.

Struc: 52 a.a.

Enzyme reactions

• Enzyme class: E.C.?

DOI no: 10.1016/j.jmb.2005.01.017

J Mol Biol 347:465-477 (2005)

PubMed id: 15740753

Solution structures of the core light-harvesting alpha and beta polypeptides from Rhodospirillum rubrum: implications for the pigment-protein and protein-protein interactions.

Z.Y.Wang, K.Gokan, M.Kobayashi, T.Nozawa.

ABSTRACT

We have determined the solution structures of the core light-harvesting (LH1) alpha and beta-polypeptides from wild-type purple photosynthetic bacterium Rhodospirillum rubrum using multidimensional NMR spectroscopy. The two polypeptides form stable alpha helices in organic solution. The structure of alpha-polypeptide consists of a long helix of 32 amino acid residues over the central transmembrane domain and a short helical segment at the N terminus that is followed by a three-residue loop. Pigment-coordinating histidine residue (His29) in the alpha-polypeptide is located near the middle of the central helix. The structure of beta-polypeptide shows a single helix of 32 amino acid residues in the membrane-spanning region with the pigment-coordinating histidine residue (His38) at a position close to the C-terminal end of the helix. Strong hydrogen bonds have been identified for the backbone amide protons over the central helical regions, indicating a rigid property of the two polypeptides. The overall structures of the R.rubrum LH1 alpha and beta-polypeptides are different from those previously reported for the LH1 beta-polypeptide of Rhodobacter sphaeroides, but are very similar to the structures of the corresponding LH2 alpha and beta-polypeptides determined by X-ray crystallography. A model constructed for the structural subunit (B820) of LH1 complex using the solution structures reveals several important features on the interactions between the LH1 alpha and beta-polypeptides. The significance of the N-terminal regions of the two polypeptides for stabilizing both B820 and LH1 complexes, as clarified by many experiments, may be attributed to the interactions between the short N-terminal helix (Trp2-Gln6) of alpha-polypeptide and a GxxxG motif in the beta-polypeptide.

Selected figure(s)

Figure 7.
Figure 7. A model for the B820 subunit constructed using the LH1 a and b structures of this study and BChl a molecules. The structure of BChl a was adopted from the crystal structure of LH2 complex (PDB entry 1LGH) determined for Ps. molischianum. (a) Side view showing the BChl a alignment in the transmembrane helical domains and relative position of the N-terminal helix and loop of the a-polypeptide to the helical region of the b-polypeptide. (b) Top view of the structure in (a) from the C terminus showing the partial overlap between the two BChl a molecules colored in cyan.

The above figure is reprinted by permission from Elsevier: J Mol Biol (2005, 347, 465-477) copyright 2005.

Figure was selected by an automated process.