1xrd
From Proteopedia
|
Light-Harvesting Complex 1 Alfa Subunit from Wild-Type Rhodospirillum rubrum
Overview
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.
About this Structure
1XRD is a Single protein structure of sequence from Rhodospirillum rubrum. Full crystallographic information is available from OCA.
Reference
Solution structures of the core light-harvesting alpha and beta polypeptides from Rhodospirillum rubrum: implications for the pigment-protein and protein-protein interactions., Wang ZY, Gokan K, Kobayashi M, Nozawa T, J Mol Biol. 2005 Mar 25;347(2):465-77. Epub 2005 Jan 25. PMID:15740753
Page seeded by OCA on Wed Nov 21 06:17:20 2007
