ID   RBS_NOSS1               Reviewed;         109 AA.
AC   P06514;
DT   01-JAN-1988, integrated into UniProtKB/Swiss-Prot.
DT   01-JAN-1988, sequence version 1.
DT   25-MAY-2022, entry version 121.
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};
GN   Synonyms=rbcS {ECO:0000255|HAMAP-Rule:MF_00859,
GN   ECO:0000303|PubMed:6091125}; OrderedLocusNames=alr1526;
OS   Nostoc sp. (strain PCC 7120 / SAG 25.82 / UTEX 2576).
OC   Bacteria; Cyanobacteria; Nostocales; Nostocaceae; Nostoc.
OX   NCBI_TaxID=103690;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA], INDUCTION, AND OPERON STRUCTURE.
RC   STRAIN=PCC 7120 / SAG 25.82 / UTEX 2576;
RX   PubMed=6091125; DOI=10.1073/pnas.81.19.5961;
RA   Nierzwicki-Bauer S.A., Curtis S.E., Haselkorn R.;
RT   "Cotranscription of genes encoding the small and large subunits of
RT   ribulose-1,5-bisphosphate carboxylase in the cyanobacterium Anabaena
RT   7120.";
RL   Proc. Natl. Acad. Sci. U.S.A. 81:5961-5965(1984).
RN   [2]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=PCC 7120 / SAG 25.82 / UTEX 2576;
RX   PubMed=11759840; DOI=10.1093/dnares/8.5.205;
RA   Kaneko T., Nakamura Y., Wolk C.P., Kuritz T., Sasamoto S., Watanabe A.,
RA   Iriguchi M., Ishikawa A., Kawashima K., Kimura T., Kishida Y., Kohara M.,
RA   Matsumoto M., Matsuno A., Muraki A., Nakazaki N., Shimpo S., Sugimoto M.,
RA   Takazawa M., Yamada M., Yasuda M., Tabata S.;
RT   "Complete genomic sequence of the filamentous nitrogen-fixing
RT   cyanobacterium Anabaena sp. strain PCC 7120.";
RL   DNA Res. 8:205-213(2001).
RN   [3]
RP   SUBCELLULAR LOCATION.
RC   STRAIN=PCC 7120 / SAG 25.82 / UTEX 2576;
RX   PubMed=24907906; DOI=10.1007/s11120-014-0018-4;
RA   de Araujo C., Arefeen D., Tadesse Y., Long B.M., Price G.D., Rowlett R.S.,
RA   Kimber M.S., Espie G.S.;
RT   "Identification and characterization of a carboxysomal gamma-carbonic
RT   anhydrase from the cyanobacterium Nostoc sp. PCC 7120.";
RL   Photosyn. Res. 121:135-150(2014).
RN   [4] {ECO:0007744|PDB:6LRR, ECO:0007744|PDB:6LRS}
RP   STRUCTURE BY ELECTRON MICROSCOPY (3.37 ANGSTROMS) IN COMPLEX WITH RBCL AND
RP   RAF1, FUNCTION, RUBISCO FOLDING AND ASSEMBLY, AND SUBUNIT.
RC   STRAIN=PCC 7120 / SAG 25.82 / UTEX 2576;
RX   PubMed=32451445; DOI=10.1038/s41477-020-0665-8;
RA   Xia L.Y., Jiang Y.L., Kong W.W., Sun H., Li W.F., Chen Y., Zhou C.Z.;
RT   "Molecular basis for the assembly of RuBisCO assisted by the chaperone
RT   Raf1.";
RL   Nat. Plants 6:708-717(2020).
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, ECO:0000269|PubMed:32451445}.
CC   -!- SUBUNIT: Heterohexadecamer of 8 large and 8 small subunits
CC       (PubMed:32451445). Forms complexes of many stoichiometries with Raf1
CC       and RbcL (PubMed:32451445). {ECO:0000269|PubMed:32451445}.
CC   -!- SUBCELLULAR LOCATION: Carboxysome {ECO:0000255|HAMAP-Rule:MF_00859,
CC       ECO:0000269|PubMed:24907906}. Note=This cyanobacterium makes beta-type
CC       carboxysomes (PubMed:24907906). In the carboxysome RuBisCO is organized
CC       into a paracrystalline array (By similarity).
CC       {ECO:0000250|UniProtKB:Q31NB2, ECO:0000269|PubMed:24907906}.
CC   -!- INDUCTION: Part of the rbcL-rbcS operon, transcribed in light and
CC       constitutively during growth on fructose. {ECO:0000269|PubMed:6091125}.
CC   -!- MISCELLANEOUS: RuBisCO folding and assembly commences when the nascent
CC       large subunit folds with the help of chaperonin GroEL-GroES. Both RbcX
CC       and Raf1 help folded RbcL release from the chaperonin and dimerize;
CC       dimeric Raf1 binds to RbcL(2) leading to an RbcL8-Raf1(8) complex. RbcS
CC       displaces Raf1, resulting in holoenzyme formation.
CC       {ECO:0000269|PubMed:32451445}.
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, ECO:0000269|PubMed:32451445}.
CC   -!- SIMILARITY: Belongs to the RuBisCO small chain family.
CC       {ECO:0000255|HAMAP-Rule:MF_00859}.
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DR   EMBL; J01540; AAA22042.1; -; Genomic_DNA.
DR   EMBL; L02520; AAA22025.1; -; Genomic_DNA.
DR   EMBL; L02521; AAA22026.1; -; Genomic_DNA.
DR   EMBL; L02522; AAA22030.1; -; Genomic_DNA.
DR   EMBL; BA000019; BAB77892.1; -; Genomic_DNA.
DR   PIR; AH1996; AH1996.
DR   RefSeq; WP_010995695.1; NZ_RSCN01000022.1.
DR   PDB; 6LRR; EM; 3.37 A; Q/R/T/U/V/W/X/Y=1-109.
DR   PDB; 6LRS; EM; 3.37 A; Q/R/S/T=1-109.
DR   PDB; 6Z1F; EM; 2.86 A; I/J/K/L/M/N/O/P=1-109.
DR   PDB; 6Z1G; EM; 8.20 A; D/E=1-109.
DR   PDBsum; 6LRR; -.
DR   PDBsum; 6LRS; -.
DR   PDBsum; 6Z1F; -.
DR   PDBsum; 6Z1G; -.
DR   AlphaFoldDB; P06514; -.
DR   SMR; P06514; -.
DR   STRING; 103690.17135346; -.
DR   EnsemblBacteria; BAB77892; BAB77892; BAB77892.
DR   KEGG; ana:alr1526; -.
DR   eggNOG; COG4451; Bacteria.
DR   OMA; KQCQVLS; -.
DR   OrthoDB; 1708389at2; -.
DR   Proteomes; UP000002483; Chromosome.
DR   GO; GO:0031470; C:carboxysome; IDA:UniProtKB.
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   3D-structure; Bacterial microcompartment; Calvin cycle;
KW   Carbon dioxide fixation; Carboxysome; Photorespiration; Photosynthesis;
KW   Reference proteome.
FT   CHAIN           1..109
FT                   /note="Ribulose bisphosphate carboxylase small subunit"
FT                   /id="PRO_0000198610"
FT   STRAND          11..13
FT                   /evidence="ECO:0007829|PDB:6LRR"
FT   STRAND          15..17
FT                   /evidence="ECO:0007829|PDB:6Z1F"
FT   HELIX           21..34
FT                   /evidence="ECO:0007829|PDB:6Z1F"
FT   STRAND          37..45
FT                   /evidence="ECO:0007829|PDB:6Z1F"
FT   HELIX           66..79
FT                   /evidence="ECO:0007829|PDB:6Z1F"
FT   STRAND          83..91
FT                   /evidence="ECO:0007829|PDB:6Z1F"
FT   TURN            92..95
FT                   /evidence="ECO:0007829|PDB:6Z1F"
FT   STRAND          96..104
FT                   /evidence="ECO:0007829|PDB:6Z1F"
SQ   SEQUENCE   109 AA;  12827 MW;  00AF32BB0A703595 CRC64;
     MQTLPKERRY ETLSYLPPLT DVQIEKQVQY ILSQGYIPAV EFNEVSEPTE LYWTLWKLPL
     FGAKTSREVL AEVQSCRSQY PGHYIRVVGF DNIKQCQILS FIVHKPSRY