ID   PHEA3_HEMAN             Reviewed;         116 AA.
AC   U5T8F7;
DT   25-MAY-2022, integrated into UniProtKB/Swiss-Prot.
DT   22-JAN-2014, sequence version 1.
DT   03-AUG-2022, entry version 17.
DE   RecName: Full=Phycoerythrin alpha-3 subunit {ECO:0000305};
OS   Hemiselmis andersenii (Cryptophyte alga).
OG   Plastid; Chloroplast {ECO:0000312|EMBL:AGY96991.1}.
OC   Eukaryota; Cryptophyceae; Cryptomonadales; Hemiselmidaceae; Hemiselmis.
OX   NCBI_TaxID=464988 {ECO:0000312|EMBL:AGY96991.1};
RN   [1] {ECO:0000312|EMBL:AGY96991.1}
RP   NUCLEOTIDE SEQUENCE [MRNA].
RC   STRAIN=CCMP644 {ECO:0000312|EMBL:AGY96991.1};
RX   PubMed=24979784; DOI=10.1073/pnas.1402538111;
RA   Harrop S.J., Wilk K.E., Dinshaw R., Collini E., Mirkovic T., Teng C.Y.,
RA   Oblinsky D.G., Green B.R., Hoef-Emden K., Hiller R.G., Scholes G.D.,
RA   Curmi P.M.;
RT   "Single-residue insertion switches the quaternary structure and exciton
RT   states of cryptophyte light-harvesting proteins.";
RL   Proc. Natl. Acad. Sci. U.S.A. 111:E2666-E2675(2014).
CC   -!- FUNCTION: Light-harvesting photosynthetic tetrapyrrole chromophore-
CC       protein from the phycobiliprotein complex. {ECO:0000305}.
CC   -!- SUBUNIT: Heterotetramer of 2 different alpha chains and 2 identical
CC       beta chains which form 2 alpha-beta heterodimers within the
CC       heterotetramer. The two alpha-beta heterodimers are rotated to an open
CC       configuration in contrast to the closed configuration found in other
CC       cryptophyte species due to the insertion of a single amino acid, Asp-
CC       65, in a conserved region of the alpha chain. In the open form, the
CC       central chromophores are not in physical contact but are separated by a
CC       water-filled channel. {ECO:0000250|UniProtKB:U5TBU5}.
CC   -!- SUBCELLULAR LOCATION: Plastid, chloroplast thylakoid membrane
CC       {ECO:0000305}; Peripheral membrane protein {ECO:0000305}; Lumenal side
CC       {ECO:0000305}.
CC   -!- PTM: Contains three phycoerythrobilin chromophores with binding
CC       mediated by both the alpha and beta subunits.
CC       {ECO:0000250|UniProtKB:U5TBU5}.
CC   -!- MISCELLANEOUS: The light-harvesting system in Cryptophytes contains
CC       phycobiliprotein complexes. Unusually they are composed of either
CC       phycoerythrin (CPE) or phycocyanin (CPC) but never allophycocyanin
CC       (APC), with only one type of biliprotein being present in any one
CC       species. Unlike cyanobacteria or red algae these proteins are not
CC       arranged into higher-order phycobilisome complexes, and they are found
CC       in the thylakoid lumen. {ECO:0000305}.
CC   -!- SIMILARITY: Belongs to the phycoerythrin family. {ECO:0000305}.
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DR   EMBL; KF314694; AGY96991.1; -; mRNA.
DR   SMR; U5T8F7; -.
DR   GO; GO:0009535; C:chloroplast thylakoid membrane; IEA:UniProtKB-SubCell.
DR   GO; GO:0030089; C:phycobilisome; IEA:InterPro.
DR   GO; GO:0015979; P:photosynthesis; IEA:UniProtKB-KW.
DR   Gene3D; 3.90.510.10; -; 1.
DR   InterPro; IPR011070; Globular_prot_asu/bsu.
DR   InterPro; IPR037011; Phycoerythr-like_a_sf.
DR   InterPro; IPR004228; Phycoerythr_a.
DR   Pfam; PF02972; Phycoerythr_ab; 1.
DR   SUPFAM; SSF56568; SSF56568; 1.
PE   3: Inferred from homology;
KW   Bile pigment; Chloroplast; Chromophore; Electron transport; Membrane;
KW   Photosynthesis; Plastid; Thylakoid; Transport.
FT   CHAIN           1..116
FT                   /note="Phycoerythrin alpha-3 subunit"
FT                   /evidence="ECO:0000255"
FT                   /id="PRO_5004664571"
FT   BINDING         53
FT                   /ligand="(2R,3E)-phycoerythrobilin"
FT                   /ligand_id="ChEBI:CHEBI:85276"
FT                   /ligand_label="1"
FT                   /ligand_note="ligand shared with beta subunit"
FT                   /evidence="ECO:0000250|UniProtKB:U5TBU5"
FT   BINDING         63
FT                   /ligand="(2R,3E)-phycoerythrobilin"
FT                   /ligand_id="ChEBI:CHEBI:85276"
FT                   /ligand_label="2"
FT                   /ligand_note="ligand shared with beta subunit"
FT                   /evidence="ECO:0000250|UniProtKB:U5TBU5"
FT   BINDING         64
FT                   /ligand="(2R,3E)-phycoerythrobilin"
FT                   /ligand_id="ChEBI:CHEBI:85276"
FT                   /ligand_label="3"
FT                   /ligand_note="ligand shared with beta subunit"
FT                   /evidence="ECO:0000250|UniProtKB:U5TBU5"
FT   BINDING         67
FT                   /ligand="(2R,3E)-phycoerythrobilin"
FT                   /ligand_id="ChEBI:CHEBI:85276"
FT                   /ligand_label="2"
FT                   /ligand_note="ligand shared with beta subunit"
FT                   /note="covalent"
FT                   /evidence="ECO:0000250|UniProtKB:U5TBU5"
FT   BINDING         85
FT                   /ligand="(2R,3E)-phycoerythrobilin"
FT                   /ligand_id="ChEBI:CHEBI:85276"
FT                   /ligand_label="2"
FT                   /ligand_note="ligand shared with beta subunit"
FT                   /evidence="ECO:0000250|UniProtKB:U5TBU5"
SQ   SEQUENCE   116 AA;  12033 MW;  021A705B2C8AADA6 CRC64;
     MMSKIVLVGL VGSAAAFNAP MMTVRRDAIA TGAAAAVVAP ILRPAGAAMK KNSKAPCVTI
     FDERDGCGGP TRAKTGAGEE GLMVKIQMQE IKLGRGAGAE YVSIFTNYDK KLFGVK