ID   RBS_PROMP               Reviewed;         113 AA.
AC   Q7V2C9;
DT   10-FEB-2021, integrated into UniProtKB/Swiss-Prot.
DT   01-OCT-2003, sequence version 1.
DT   25-MAY-2022, entry version 97.
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=cbbS {ECO:0000255|HAMAP-Rule:MF_00859, ECO:0000303|PubMed:22155772};
GN   Synonyms=rbcS {ECO:0000255|HAMAP-Rule:MF_00859}; OrderedLocusNames=PMM0551;
OS   Prochlorococcus marinus subsp. pastoris (strain CCMP1986 / NIES-2087 /
OS   MED4).
OC   Bacteria; Cyanobacteria; Synechococcales; Prochlorococcaceae;
OC   Prochlorococcus.
OX   NCBI_TaxID=59919;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=CCMP1986 / NIES-2087 / MED4;
RX   PubMed=12917642; DOI=10.1038/nature01947;
RA   Rocap G., Larimer F.W., Lamerdin J.E., Malfatti S., Chain P., Ahlgren N.A.,
RA   Arellano A., Coleman M., Hauser L., Hess W.R., Johnson Z.I., Land M.L.,
RA   Lindell D., Post A.F., Regala W., Shah M., Shaw S.L., Steglich C.,
RA   Sullivan M.B., Ting C.S., Tolonen A., Webb E.A., Zinser E.R.,
RA   Chisholm S.W.;
RT   "Genome divergence in two Prochlorococcus ecotypes reflects oceanic niche
RT   differentiation.";
RL   Nature 424:1042-1047(2003).
RN   [2]
RP   FUNCTION, CATALYTIC ACTIVITY, BIOPHYSICOCHEMICAL PROPERTIES, PROTEIN
RP   ABUNDANCE, AND SUBCELLULAR LOCATION.
RC   STRAIN=CCMP1986 / NIES-2087 / MED4;
RX   PubMed=22155772; DOI=10.1128/jb.06444-11;
RA   Roberts E.W., Cai F., Kerfeld C.A., Cannon G.C., Heinhorst S.;
RT   "Isolation and characterization of the Prochlorococcus carboxysome reveal
RT   the presence of the novel shell protein CsoS1D.";
RL   J. Bacteriol. 194:787-795(2012).
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       (PubMed:22155772). There are estimated to be 152 RuBisCO holoenzymes
CC       per carboxysome (PubMed:22155772). {ECO:0000269|PubMed:22155772}.
CC   -!- BIOPHYSICOCHEMICAL PROPERTIES:
CC       Kinetic parameters:
CC         KM=169.3 uM for D-ribulose 1,5-bisphosphate
CC         {ECO:0000269|PubMed:22155772};
CC         Vmax=1.28 umol/min/mg enzyme {ECO:0000269|PubMed:22155772};
CC         Note=From purified carboxysomes. {ECO:0000269|PubMed:22155772};
CC   -!- SUBUNIT: Heterohexadecamer of 8 large and 8 small subunits. Forms a
CC       CsoS2-CsoS1-RuBisCO complex. {ECO:0000250|UniProtKB:P45686,
CC       ECO:0000255|HAMAP-Rule:MF_00859}.
CC   -!- SUBCELLULAR LOCATION: Carboxysome {ECO:0000255|HAMAP-Rule:MF_00859,
CC       ECO:0000269|PubMed:22155772}. Note=This bacterium makes alpha-type
CC       carboxysomes. {ECO:0000269|PubMed:22155772}.
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; BX548174; CAE19010.1; -; Genomic_DNA.
DR   RefSeq; WP_011132185.1; NC_005072.1.
DR   AlphaFoldDB; Q7V2C9; -.
DR   SMR; Q7V2C9; -.
DR   STRING; 59919.PMM0551; -.
DR   EnsemblBacteria; CAE19010; CAE19010; PMM0551.
DR   KEGG; pmm:PMM0551; -.
DR   eggNOG; COG4451; Bacteria.
DR   HOGENOM; CLU_098114_2_0_3; -.
DR   OMA; KQCQVLS; -.
DR   OrthoDB; 1708389at2; -.
DR   Proteomes; UP000001026; Chromosome.
DR   GO; GO:0031470; C:carboxysome; IEA:UniProtKB-SubCell.
DR   GO; GO:0009853; P:photorespiration; IEA:UniProtKB-KW.
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   1: Evidence at protein level;
KW   Bacterial microcompartment; Calvin cycle; Carbon dioxide fixation;
KW   Carboxysome; Photorespiration; Photosynthesis.
FT   CHAIN           1..113
FT                   /note="Ribulose bisphosphate carboxylase small subunit"
FT                   /id="PRO_0000452049"
SQ   SEQUENCE   113 AA;  12940 MW;  7E1DCADE61BC1F0D CRC64;
     MPFQSSVGDY QTVATLETFG FLPPMTQEEI YDQIAYIIAQ GWSPVIEHVH PSGSMQTYWS
     YWKLPFFGEK DLNLVVSELE ACHRAYPDHH VRIIGYDAYT QSQGTAFAVF QGR