ID   RBS_CYACA               Reviewed;         138 AA.
AC   P37394; Q9TLY3;
DT   01-OCT-1994, integrated into UniProtKB/Swiss-Prot.
DT   01-OCT-1994, sequence version 1.
DT   25-MAY-2022, entry version 94.
DE   RecName: Full=Ribulose bisphosphate carboxylase small subunit {ECO:0000255|HAMAP-Rule:MF_00859};
DE            Short=RuBisCO small subunit {ECO:0000255|HAMAP-Rule:MF_00859};
GN   Name=rbcS {ECO:0000255|HAMAP-Rule:MF_00859};
OS   Cyanidium caldarium (Red alga).
OG   Plastid; Chloroplast.
OC   Eukaryota; Rhodophyta; Bangiophyceae; Cyanidiales; Cyanidiaceae; Cyanidium.
OX   NCBI_TaxID=2771;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RC   STRAIN=RK-1;
RA   Langsdorf A., Emich A., Zetsche K.;
RT   "A thioredoxin gene is located upstream of rbcLS in the unicellular red
RT   alga Cyanidium caldarium, strain RK-1.";
RL   Submitted (FEB-1993) to the EMBL/GenBank/DDBJ databases.
RN   [2]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=RK-1;
RX   PubMed=11040290; DOI=10.1007/s002390010101;
RA   Gloeckner G., Rosenthal A., Valentin K.-U.;
RT   "The structure and gene repertoire of an ancient red algal plastid
RT   genome.";
RL   J. Mol. Evol. 51:382-390(2000).
CC   -!- FUNCTION: RuBisCO catalyzes two reactions: the carboxylation of D-
CC       ribulose 1,5-bisphosphate, the primary event in carbon dioxide
CC       fixation, as well as the oxidative fragmentation of the pentose
CC       substrate in the photorespiration process. Both reactions occur
CC       simultaneously and in competition at the same active site. Although the
CC       small subunit is not catalytic it is essential for maximal activity.
CC       {ECO:0000255|HAMAP-Rule:MF_00859}.
CC   -!- SUBUNIT: Heterohexadecamer of 8 large and 8 small subunits.
CC       {ECO:0000255|HAMAP-Rule:MF_00859}.
CC   -!- SUBCELLULAR LOCATION: Plastid, chloroplast {ECO:0000255|HAMAP-
CC       Rule:MF_00859}.
CC   -!- MISCELLANEOUS: In this alga, in contrast to plants, the small subunit
CC       is encoded in the chloroplast.
CC   -!- MISCELLANEOUS: The basic functional RuBisCO is composed of a large
CC       chain homodimer in a 'head-to-tail' conformation. In form I RuBisCO
CC       this homodimer is arranged in a barrel-like tetramer with the small
CC       subunits forming a tetrameric 'cap' on each end of the 'barrel'.
CC       {ECO:0000255|HAMAP-Rule:MF_00859}.
CC   -!- SIMILARITY: Belongs to the RuBisCO small chain family.
CC       {ECO:0000255|HAMAP-Rule:MF_00859}.
CC   -!- SEQUENCE CAUTION:
CC       Sequence=AAF12959.1; Type=Erroneous initiation; Note=Truncated N-terminus.; Evidence={ECO:0000305};
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DR   EMBL; Z21723; CAA79822.2; -; Genomic_DNA.
DR   EMBL; AF022186; AAF12959.1; ALT_INIT; Genomic_DNA.
DR   PIR; S31917; S31917.
DR   RefSeq; NP_045135.2; NC_001840.1.
DR   AlphaFoldDB; P37394; -.
DR   SMR; P37394; -.
DR   GeneID; 800300; -.
DR   GO; GO:0009507; C:chloroplast; IEA:UniProtKB-SubCell.
DR   GO; GO:0019253; P:reductive pentose-phosphate cycle; IEA:UniProtKB-KW.
DR   CDD; cd03527; RuBisCO_small; 1.
DR   Gene3D; 3.30.190.10; -; 1.
DR   HAMAP; MF_00859; RuBisCO_S_bact; 1.
DR   InterPro; IPR024681; RuBisCO_ssu.
DR   InterPro; IPR000894; RuBisCO_ssu_dom.
DR   InterPro; IPR036385; RuBisCO_ssu_sf.
DR   PANTHER; PTHR31262; PTHR31262; 1.
DR   Pfam; PF00101; RuBisCO_small; 1.
DR   SMART; SM00961; RuBisCO_small; 1.
DR   SUPFAM; SSF55239; SSF55239; 1.
PE   3: Inferred from homology;
KW   Calvin cycle; Carbon dioxide fixation; Chloroplast; Photorespiration;
KW   Photosynthesis; Plastid.
FT   CHAIN           1..138
FT                   /note="Ribulose bisphosphate carboxylase small subunit"
FT                   /id="PRO_0000198592"
SQ   SEQUENCE   138 AA;  16205 MW;  E43D92B083BA9BA0 CRC64;
     MRVTQGTFSF LPDLTNDQIR KQIQYAINKG WALSVEYTDD PHPRNSYWEM WGLPLFDVKD
     PAAIMFEVEA CRKEKSNYYI KLLAFDSTKG VESTAMSFMV NRPAHEPGFV LRRIESNDRV
     QRYQIHSYAT EKPEGERY