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'''Light-Harvesting Complex 1 Alfa Subunit from Wild-Type Rhodospirillum rubrum'''<br /> | '''Light-Harvesting Complex 1 Alfa Subunit from Wild-Type Rhodospirillum rubrum'''<br /> | ||
==Overview== | ==Overview== | ||
| - | We have determined the solution structures of the core light-harvesting | + | 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== | ==About this Structure== | ||
| - | 1XRD is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Rhodospirillum_rubrum Rhodospirillum rubrum]. Full crystallographic information is available from [http:// | + | 1XRD is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Rhodospirillum_rubrum Rhodospirillum rubrum]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1XRD OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Kobayashi, M.]] | [[Category: Kobayashi, M.]] | ||
[[Category: Nozawa, T.]] | [[Category: Nozawa, T.]] | ||
| - | [[Category: Wang, Z | + | [[Category: Wang, Z Y.]] |
[[Category: light-harvesting]] | [[Category: light-harvesting]] | ||
[[Category: membrane spanning helix]] | [[Category: membrane spanning helix]] | ||
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[[Category: pigment binding]] | [[Category: pigment binding]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:57:53 2008'' |
Revision as of 13:57, 21 February 2008
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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
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