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48  structures 110  species 1  interaction 509  sequences 1  architecture

Family: LHC (PF00556)

Summary: Antenna complex alpha/beta subunit

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This is the Wikipedia entry entitled "Bacterial antenna complex". More...

Bacterial antenna complex Edit Wikipedia article

Antenna complex alpha/beta subunit
LH2 complex drawn from PDB entry 1LGH (Koepke J et al (1996) Structure 4 581-597.png
Structure of the light-harvesting complex II.[1]
Identifiers
Symbol LHC
Pfam PF00556
InterPro IPR000066
PROSITE PDOC00748
SCOP 1lgh
SUPERFAMILY 1lgh
OPM superfamily 1
OPM protein 1lgh

Bacterial antenna complex proteins are the main light-absorbing components in photosynthetic bacteria.[1]

In photosynthetic purple bacteria the antenna complexes function as light-harvesting systems that absorb light radiation and transfer the excitation energy to the reaction centres. The antenna complexes are generally composed of two types of polypeptides (alpha and beta chains) which are arranged in a ring-like fashion creating a cylinder that spans the membrane; the proteins bind two or three types of bacteriochlorophyll (BChl) molecules and different types of carotenoids depending on the species.[2][3] Both the alpha and the beta chains of antenna complexes are small proteins of 42 to 68 residues which share a three-domain organization. They are composed of a N-terminal hydrophilic cytoplasmic domain followed by a transmembrane region and a C-terminal hydrophilic periplasmic domain. In the transmembrane region of both chains there is a conserved histidine which is most probably involved in the binding of the magnesium atom of a bacteriochlorophyll group. The beta chains contain an additional conserved histidine which is located at the C-terminal extremity of the cytoplasmic domain and which is also thought to be involved in bacteriochlorophyll-binding.

Subfamilies[edit]

References[edit]

  1. ^ a b Koepke J, Hu X, Muenke C, Schulten K, Michel H (May 1996). "The crystal structure of the light-harvesting complex II (B800-850) from Rhodospirillum molischianum". Structure 4 (5): 581–97. doi:10.1016/S0969-2126(96)00063-9. PMID 8736556. 
  2. ^ Wagner-Huber R, Brunisholz RA, Bissig I, Frank G, Suter F, Zuber H (1992). "The primary structure of the antenna polypeptides of Ectothiorhodospira halochloris and Ectothiorhodospira halophila. Four core-type antenna polypeptides in E. halochloris and E. halophila". Eur. J. Biochem. 205 (3): 917–925. doi:10.1111/j.1432-1033.1992.tb16858.x. PMID 1577009. 
  3. ^ Brunisholz RA, Zuber H (1992). "Structure, function and organization of antenna polypeptides and antenna complexes from the three families of Rhodospirillaneae". J. Photochem. Photobiol. B 15 (1): 113–140. doi:10.1016/1011-1344(92)87010-7. PMID 1460542. 

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Literature references

  1. Koepke J, Hu X, Muenke C, Schulten K, Michel H; , Structure 1996;4:581-597.: The crystal structure of the light-harvesting complex II (B800-850) from Rhodospirillum molischianum. PUBMED:8736556 EPMC:8736556


Internal database links

External database links

This tab holds annotation information from the InterPro database.

InterPro entry IPR000066

The antenna complexes of photosynthetic bacteria function as light-harvesting systems that absorb light and transfer the excitation energy to the reaction centres. The antenna complexes usually comprise 2 polypeptides (alpha- and beta-chains), 2-3 bacteriochlorophyll molecules and some carotenoids [PUBMED:1577009, PUBMED:1460542]. The alpha- and beta-chains are small proteins of 40-70 residues. Each has an N-terminal hydrophilic cytoplasmic domain, a single transmembrane (TM) region, and a small C-terminal hydrophilic periplasmic domain. In both chains, the TM domain houses a conserved His residue, presumed to be involved in binding the magnesium atom of a bacteriochlorophyll group. The beta-chains are characterised by a further histidine at the C-terminal extremity of the cytoplasmic domain, which is also thought to be involved in bacteriochlorophyll binding.

Gene Ontology

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Domain organisation

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Alignments

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(28)
Full
(509)
Representative proteomes NCBI
(438)
Meta
(71)
RP15
(40)
RP35
(76)
RP55
(92)
RP75
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Format an alignment

  Seed
(28)
Full
(509)
Representative proteomes NCBI
(438)
Meta
(71)
RP15
(40)
RP35
(76)
RP55
(92)
RP75
(157)
Alignment:
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We make all of our alignments available in Stockholm format. You can download them here as raw, plain text files or as gzip-compressed files.

  Seed
(28)
Full
(509)
Representative proteomes NCBI
(438)
Meta
(71)
RP15
(40)
RP35
(76)
RP55
(92)
RP75
(157)
Raw Stockholm Download   Download   Download   Download   Download   Download   Download   Download  
Gzipped Download   Download   Download   Download   Download   Download   Download   Download  

You can also download a FASTA format file containing the full-length sequences for all sequences in the full alignment.

External links

MyHits provides a collection of tools to handle multiple sequence alignments. For example, one can refine a seed alignment (sequence addition or removal, re-alignment or manual edition) and then search databases for remote homologs using HMMER3.

Pfam alignments:

HMM logo

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Trees

This page displays the phylogenetic tree for this family's seed alignment. We use FastTree to calculate neighbour join trees with a local bootstrap based on 100 resamples (shown next to the tree nodes). FastTree calculates approximately-maximum-likelihood phylogenetic trees from our seed alignment.

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Curation and family details

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Curation View help on the curation process

Seed source: SCOP
Previous IDs: none
Type: Domain
Author: Bateman A
Number in seed: 28
Number in full: 509
Average length of the domain: 38.60 aa
Average identity of full alignment: 27 %
Average coverage of the sequence by the domain: 65.17 %

HMM information View help on HMM parameters

HMM build commands:
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 23193494 -E 1000 --cpu 4 HMM pfamseq
Model details:
Parameter Sequence Domain
Gathering cut-off 20.5 20.5
Trusted cut-off 20.8 20.5
Noise cut-off 20.2 20.4
Model length: 40
Family (HMM) version: 15
Download: download the raw HMM for this family

Species distribution

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Interactions

There is 1 interaction for this family. More...

LHC

Structures

For those sequences which have a structure in the Protein DataBank, we use the mapping between UniProt, PDB and Pfam coordinate systems from the PDBe group, to allow us to map Pfam domains onto UniProt sequences and three-dimensional protein structures. The table below shows the structures on which the LHC domain has been found. There are 48 instances of this domain found in the PDB. Note that there may be multiple copies of the domain in a single PDB structure, since many structures contain multiple copies of the same protein seqence.

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