ID   RBS_CYLSN               Reviewed;         139 AA.
AC   P24683;
DT   01-MAR-1992, integrated into UniProtKB/Swiss-Prot.
DT   01-MAR-1992, sequence version 1.
DT   25-MAY-2022, entry version 89.
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}; Synonyms=ssu8;
OS   Cylindrotheca sp. (strain N1) (Marine diatom).
OG   Plastid; Chloroplast.
OC   Eukaryota; Sar; Stramenopiles; Ochrophyta; Bacillariophyta;
OC   Bacillariophyceae; Bacillariophycidae; Bacillariales; Bacillariaceae;
OC   Cylindrotheca; unclassified Cylindrotheca.
OX   NCBI_TaxID=2855;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=1706714; DOI=10.1016/s0021-9258(18)38114-6;
RA   Hwang S.-R., Tabita F.R.;
RT   "Cotranscription, deduced primary structure, and expression of the
RT   chloroplast-encoded rbcL and rbcS genes of the marine diatom Cylindrotheca
RT   sp. strain N1.";
RL   J. Biol. Chem. 266:6271-6279(1991).
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: 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}.
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DR   EMBL; M59080; AAA84193.1; -; Genomic_DNA.
DR   PIR; B38728; RKQMSY.
DR   AlphaFoldDB; P24683; -.
DR   SMR; P24683; -.
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..139
FT                   /note="Ribulose bisphosphate carboxylase small subunit"
FT                   /id="PRO_0000198595"
SQ   SEQUENCE   139 AA;  15936 MW;  E6E67FE738E499B4 CRC64;
     MRLTQGCFSF LPDLTDEQIE KQVNYAISKG WAMNVEWTDD PHPRNNYWEL WGLPLFDIKD
     PASVMFELQE ARKACAAGYI RMNAFDASYG TESCVMSFIV NRPANEPGFY LERAEGKGRQ
     INYTIKSYSV QANPEGGRY