ID   PHAA_NEOYE              Reviewed;         161 AA.
AC   P59856; Q1XDM5;
DT   26-SEP-2003, integrated into UniProtKB/Swiss-Prot.
DT   06-FEB-2007, sequence version 3.
DT   03-AUG-2022, entry version 89.
DE   RecName: Full=Allophycocyanin alpha chain;
GN   Name=apcA;
OS   Neopyropia yezoensis (Susabi-nori) (Pyropia yezoensis).
OG   Plastid; Chloroplast.
OC   Eukaryota; Rhodophyta; Bangiophyceae; Bangiales; Bangiaceae; Neopyropia.
OX   NCBI_TaxID=2788;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=U-51;
RA   Kunimoto M., Morishima K., Yoshikawa M., Fukuda S., Kobayashi T.,
RA   Kobayashi M., Okazaki T., Ohara I., Nakayama I.;
RT   "Whole genome sequence of Porphyra yezoensis chloroplast.";
RL   Submitted (NOV-2003) to the EMBL/GenBank/DDBJ databases.
RN   [2]
RP   CRYSTALLIZATION.
RX   PubMed=9761868; DOI=10.1107/s0907444997017824;
RA   Liu J.-Y., Zhang J.-P., Wan Z.-L., Liang D.-C., Zhang J.-P., Wu H.-J.;
RT   "Crystallization and preliminary X-ray studies of allophycocyanin from red
RT   alga Porphyra yezoensis.";
RL   Acta Crystallogr. D 54:662-664(1998).
RN   [3]
RP   X-RAY CRYSTALLOGRAPHY (2.2 ANGSTROMS) IN COMPLEX WITH APCB AND
RP   PHYCOCYANOBILIN, AND SUBUNIT.
RX   PubMed=10358042; DOI=10.1074/jbc.274.24.16945;
RA   Liu J.-Y., Jiang T., Zhang J.-P., Liang D.-C.;
RT   "Crystal structure of allophycocyanin from red algae Porphyra yezoensis at
RT   2.2-A resolution.";
RL   J. Biol. Chem. 274:16945-16952(1999).
CC   -!- FUNCTION: Light-harvesting photosynthetic tetrapyrrole chromophore-
CC       protein from the phycobiliprotein complex.
CC   -!- SUBUNIT: Heterododecamer of 6 alpha and 6 beta chains. The basic
CC       functional unit of phycobiliproteins is a ring-shaped hexamer formed
CC       from two back-to-back trimers contacting via the alpha chain subunits.
CC       The trimers are composed of alpha/beta subunit heterodimers arranged
CC       around a three-fold axis of symmetry. The phycoerythrins also contain a
CC       gamma subunit which is located in the center of the hexamer.
CC       {ECO:0000269|PubMed:10358042}.
CC   -!- SUBCELLULAR LOCATION: Plastid, chloroplast thylakoid membrane;
CC       Peripheral membrane protein; Stromal side. Note=Forms the core of the
CC       phycobilisome.
CC   -!- PTM: Contains one covalently linked phycocyanobilin chromophore.
CC   -!- MISCELLANEOUS: The light-harvesting antenna system in red algae and
CC       cyanobacteria is formed of phycobilisomes. These are composed of the
CC       phycobiliproteins phycoerythrin (CPE), phycocyanin (CPC) and
CC       allophycocyanin (APC). Cyanobacteria also contain phycoerythrocyanin
CC       (PCC). The phycobiliproteins all share the same subunit composition and
CC       organization with variations in the covalently bound open-chain
CC       tetrapyrrole chromophores. The phycobiliprotein complexes are arranged
CC       sequentially in antenna complexes linked by linker proteins with CPE at
CC       the periphery, CPC in the middle and APC at the core feeding to the
CC       photosynthetic reaction center. Allophycocyanin has a maximum
CC       absorption at approximately 650 nanometers.
CC   -!- SIMILARITY: Belongs to the phycobiliprotein family. {ECO:0000305}.
CC   -!- CAUTION: Neither a protein sequence nor a nucleotide sequence had been
CC       determined for this protein when the crystallographic structure was
CC       reported. The sequence of a model fit to electron density plots at 2.2
CC       Angstroms resolution was used. When a nucleotide sequence became
CC       available, it replaced the model sequence. There are 14 differences
CC       between the model and the nucleotide sequences. {ECO:0000305}.
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DR   EMBL; AP006715; BAE92386.1; -; Genomic_DNA.
DR   RefSeq; YP_536943.1; NC_007932.1.
DR   PDB; 1KN1; X-ray; 2.20 A; A=2-161.
DR   PDBsum; 1KN1; -.
DR   AlphaFoldDB; P59856; -.
DR   SMR; P59856; -.
DR   GeneID; 3978963; -.
DR   EvolutionaryTrace; P59856; -.
DR   GO; GO:0009535; C:chloroplast thylakoid membrane; IEA:UniProtKB-SubCell.
DR   GO; GO:0030089; C:phycobilisome; IEA:UniProtKB-KW.
DR   GO; GO:0015979; P:photosynthesis; IEA:UniProtKB-KW.
DR   Gene3D; 1.10.490.20; -; 1.
DR   InterPro; IPR009050; Globin-like_sf.
DR   InterPro; IPR012128; Phycobilisome_asu/bsu.
DR   InterPro; IPR038719; Phycobilisome_asu/bsu_sf.
DR   Pfam; PF00502; Phycobilisome; 1.
DR   PIRSF; PIRSF000081; Phycocyanin; 1.
DR   SUPFAM; SSF46458; SSF46458; 1.
PE   1: Evidence at protein level;
KW   3D-structure; Antenna complex; Bile pigment; Chloroplast; Chromophore;
KW   Electron transport; Membrane; Methylation; Photosynthesis; Phycobilisome;
KW   Plastid; Thylakoid; Transport.
FT   INIT_MET        1
FT                   /note="Removed"
FT   CHAIN           2..161
FT                   /note="Allophycocyanin alpha chain"
FT                   /id="PRO_0000199085"
FT   BINDING         81
FT                   /ligand="(2R,3E)-phycocyanobilin"
FT                   /ligand_id="ChEBI:CHEBI:85275"
FT                   /note="covalent, via 1 link"
FT                   /evidence="ECO:0000269|PubMed:10358042"
FT   BINDING         83
FT                   /ligand="(2R,3E)-phycocyanobilin"
FT                   /ligand_id="ChEBI:CHEBI:85275"
FT                   /evidence="ECO:0000269|PubMed:10358042"
FT   BINDING         84
FT                   /ligand="(2R,3E)-phycocyanobilin"
FT                   /ligand_id="ChEBI:CHEBI:85275"
FT                   /evidence="ECO:0000269|PubMed:10358042"
FT   MOD_RES         71
FT                   /note="N4-methylasparagine"
FT                   /evidence="ECO:0000250"
FT   HELIX           3..13
FT                   /evidence="ECO:0007829|PDB:1KN1"
FT   HELIX           20..30
FT                   /evidence="ECO:0007829|PDB:1KN1"
FT   HELIX           33..45
FT                   /evidence="ECO:0007829|PDB:1KN1"
FT   HELIX           47..58
FT                   /evidence="ECO:0007829|PDB:1KN1"
FT   TURN            59..61
FT                   /evidence="ECO:0007829|PDB:1KN1"
FT   STRAND          66..69
FT                   /evidence="ECO:0007829|PDB:1KN1"
FT   HELIX           77..98
FT                   /evidence="ECO:0007829|PDB:1KN1"
FT   HELIX           102..108
FT                   /evidence="ECO:0007829|PDB:1KN1"
FT   TURN            109..111
FT                   /evidence="ECO:0007829|PDB:1KN1"
FT   HELIX           112..119
FT                   /evidence="ECO:0007829|PDB:1KN1"
FT   HELIX           123..139
FT                   /evidence="ECO:0007829|PDB:1KN1"
FT   HELIX           143..158
FT                   /evidence="ECO:0007829|PDB:1KN1"
SQ   SEQUENCE   161 AA;  17509 MW;  B7CBFCD1B53EC571 CRC64;
     MSIVTKSIVN ADAEARYLSP GELDRIKSFV LSGQRRLRIA QILTDNRERI VKQGGQQLFQ
     KRPDVVSPGG NAYGEEMTAT CLRDLDYYLR LVTYGIVAGD VTPIEEIGLV GVKEMYNSLG
     TPISGVAEGV KCMKSVACSL LAGEDSAEAG FYFDYTLGAM Q