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0  structures 505  species 0  interactions 562  sequences 3  architectures

Family: BtpA (PF03437)

Summary: BtpA family

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This is the Wikipedia entry entitled "BtpA protein". More...

BtpA protein Edit Wikipedia article

BtpA
Identifiers
Symbol BtpA
Pfam PF03437
Pfam clan CL0036
InterPro IPR005137

In molecular biology, the BtpA protein family is a family of proteins which includes BtpA. BtpA appears to play a role in the stabilisation of photosystem I .[1] It is an extrinsic membrane protein located on the cytoplasmic side of the thylakoid membrane.[2][1] Homologs of BtpA are found in the crenarchaeota and euryarchaeota, where their function remains unknown. The Ycf4 protein is firmly associated with the thylakoid membrane, presumably through a transmembrane domain.[3] Ycf4 co-fractionates with a protein complex larger than PSI upon sucrose density gradient centrifugation of solubilised thylakoids.[3] The Ycf3 protein is loosely associated with the thylakoid membrane and can be released from the membrane with sodium carbonate. This suggests that Ycf3 is not part of a stable complex and that it probably interacts transiently with its partners.[4] Ycf3 contains a number of tetratricopeptide repeats (TPR); TPR is a structural motif present in a wide range of proteins, which mediates protein-protein interactions.

References

  1. ^ a b Zak E, Pakrasi HB (May 2000). "The BtpA protein stabilizes the reaction center proteins of photosystem I in the cyanobacterium Synechocystis sp. PCC 6803 at low temperature". Plant Physiol. 123 (1): 215–22. doi:10.1104/pp.123.1.215. PMC 58995. PMID 10806238. 
  2. ^ Zak E, Norling B, Andersson B, Pakrasi HB (April 1999). "Subcellular localization of the BtpA protein in the cyanobacterium Synechocystis sp. PCC 6803". Eur. J. Biochem. 261 (1): 311–6. doi:10.1046/j.1432-1327.1999.00281.x. PMID 10103064. 
  3. ^ a b Boudreau E, Takahashi Y, Lemieux C, Turmel M, Rochaix JD (October 1997). "The chloroplast ycf3 and ycf4 open reading frames of Chlamydomonas reinhardtii are required for the accumulation of the photosystem I complex". EMBO J. 16 (20): 6095–104. doi:10.1093/emboj/16.20.6095. PMC 1326293. PMID 9321389. 
  4. ^ Naver H, Boudreau E, Rochaix JD (December 2001). "Functional studies of Ycf3: its role in assembly of photosystem I and interactions with some of its subunits". Plant Cell 13 (12): 2731–45. doi:10.2307/3871531. PMC 139485. PMID 11752384. 

This article incorporates text from the public domain Pfam and InterPro IPR005137

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This tab holds the annotation information that is stored in the Pfam database. As we move to using Wikipedia as our main source of annotation, the contents of this tab will be gradually replaced by the Wikipedia tab.

BtpA family Provide feedback

The BtpA protein is tightly associated with the thylakoid membranes, where it stabilises the reaction centre proteins of photosystem I.

Literature references

  1. Zak E, Pakrasi HB; , Plant Physiol 2000;123:215-222.: The BtpA protein stabilizes the reaction center proteins of photosystem I in the cyanobacterium Synechocystis sp. PCC 6803 at low temperature. PUBMED:10806238 EPMC:10806238


External database links

This tab holds annotation information from the InterPro database.

InterPro entry IPR005137

Photosystem I (PSI) is a large protein complex embedded within the photosynthetic thylakoid membrane. It consists of 11 subunits, ~100 chlorophyll a molecules, 2 phylloquinones, and 3 Fe4S4-clusters. The three dimensional structure of the PSI complex has been resolved at 2.5 A [PUBMED:11418848], which allows the precise localisation of each cofactor. PSI together with photosystem II (PSII) catalyses the light-induced steps in oxygenic photosynthesis - a process found in cyanobacteria, eukaryotic algae (e.g. red algae, green algae) and higher plants.

To date, three thylakoid proteins involved in the stable accumulation of PSI have been identified: BtpA [PUBMED:9045660], Ycf3 [PUBMED:9321389, PUBMED:9314531], and Ycf4 (INTERPRO) [PUBMED:9321389]. Because translation of the psaA and psaB mRNAs encoding the two reaction centre polypeptides, of PSI and PSII respectively, is not affected in mutant strains lacking functional ycf3 and ycf4, the products of these two genes appear to act at a post-translational step of PSI biosynthesis. These gene products are therefore involved either in the stabilisation or in the assembly of the PSI complex. However, their exact roles remain unknown. The BtpA protein appears to act at the level of PSI stabilisation [PUBMED:10806238]. It is an extrinsic membrane protein located on the cytoplasmic side of the thylakoid membrane [PUBMED:10103064, PUBMED:10806238]. Homologs of BtpA are found in the crenarchaeota and euryarchaeota, where their function remains unknown. The Ycf4 protein is firmly associated with the thylakoid membrane, presumably through a transmembrane domain [PUBMED:9321389]. Ycf4 co-fractionates with a protein complex larger than PSI upon sucrose density gradient centrifugation of solubilised thylakoids [PUBMED:9321389]. The Ycf3 protein is loosely associated with the thylakoid membrane and can be released from the membrane with sodium carbonate. This suggests that Ycf3 is not part of a stable complex and that it probably interacts transiently with its partners [PUBMED:11752384]. Ycf3 contains a number of tetratrico peptide repeats (TPR, INTERPRO); TPR is a structural motif present in a wide range of proteins, which mediates protein-protein interactions.

Domain organisation

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  Seed
(6)
Full
(562)
Representative proteomes NCBI
(689)
Meta
(382)
RP15
(60)
RP35
(104)
RP55
(151)
RP75
(178)
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  Seed
(6)
Full
(562)
Representative proteomes NCBI
(689)
Meta
(382)
RP15
(60)
RP35
(104)
RP55
(151)
RP75
(178)
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Curation View help on the curation process

Seed source: Pfam-B_4453 (release 6.6)
Previous IDs: none
Type: Family
Author: Finn RD
Number in seed: 6
Number in full: 562
Average length of the domain: 246.50 aa
Average identity of full alignment: 36 %
Average coverage of the sequence by the domain: 93.56 %

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 20.2 20.2
Trusted cut-off 20.2 20.2
Noise cut-off 20.1 20.1
Model length: 254
Family (HMM) version: 10
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