ID   RBS_SYNE7               Reviewed;         111 AA.
AC   Q31NB2;
DT   07-OCT-2020, integrated into UniProtKB/Swiss-Prot.
DT   06-DEC-2005, sequence version 1.
DT   27-MAR-2024, entry version 93.
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:17675289}; OrderedLocusNames=Synpcc7942_1427;
OS   Synechococcus elongatus (strain ATCC 33912 / PCC 7942 / FACHB-805)
OS   (Anacystis nidulans R2).
OC   Bacteria; Cyanobacteriota; Cyanophyceae; Synechococcales; Synechococcaceae;
OC   Synechococcus.
OX   NCBI_TaxID=1140;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=ATCC 33912 / PCC 7942 / FACHB-805;
RG   US DOE Joint Genome Institute;
RA   Copeland A., Lucas S., Lapidus A., Barry K., Detter J.C., Glavina T.,
RA   Hammon N., Israni S., Pitluck S., Schmutz J., Larimer F., Land M.,
RA   Kyrpides N., Lykidis A., Golden S., Richardson P.;
RT   "Complete sequence of chromosome 1 of Synechococcus elongatus PCC 7942.";
RL   Submitted (AUG-2005) to the EMBL/GenBank/DDBJ databases.
RN   [2]
RP   IDENTIFICATION BY MASS SPECTROMETRY, INTERACTION WITH CCMM, AND SUBCELLULAR
RP   LOCATION.
RC   STRAIN=ATCC 33912 / PCC 7942 / FACHB-805;
RX   PubMed=17675289; DOI=10.1074/jbc.m703896200;
RA   Long B.M., Badger M.R., Whitney S.M., Price G.D.;
RT   "Analysis of carboxysomes from Synechococcus PCC7942 reveals multiple
RT   Rubisco complexes with carboxysomal proteins CcmM and CcaA.";
RL   J. Biol. Chem. 282:29323-29335(2007).
RN   [3]
RP   SUBCELLULAR LOCATION.
RC   STRAIN=ATCC 33912 / PCC 7942 / FACHB-805;
RX   PubMed=22928045; DOI=10.1371/journal.pone.0043871;
RA   Rae B.D., Long B.M., Badger M.R., Price G.D.;
RT   "Structural determinants of the outer shell of beta-carboxysomes in
RT   Synechococcus elongatus PCC 7942: roles for CcmK2, K3-K4, CcmO, and CcmL.";
RL   PLoS ONE 7:e43871-e43871(2012).
RN   [4]
RP   CARBOXYSOME ASSEMBLY PROCESS, AND SUBCELLULAR LOCATION.
RC   STRAIN=ATCC 33912 / PCC 7942 / FACHB-805;
RX   PubMed=24267892; DOI=10.1016/j.cell.2013.10.044;
RA   Cameron J.C., Wilson S.C., Bernstein S.L., Kerfeld C.A.;
RT   "Biogenesis of a bacterial organelle: the carboxysome assembly pathway.";
RL   Cell 155:1131-1140(2013).
RN   [5]
RP   FUNCTION, CATALYTIC ACTIVITY, AND SUBCELLULAR LOCATION.
RC   STRAIN=ATCC 33912 / PCC 7942 / FACHB-805;
RX   PubMed=24585024; DOI=10.1007/s11120-014-9986-7;
RA   Nishimura T., Yamaguchi O., Takatani N., Maeda S., Omata T.;
RT   "In vitro and in vivo analyses of the role of the carboxysomal beta-type
RT   carbonic anhydrase of the cyanobacterium Synechococcus elongatus in
RT   carboxylation of ribulose-1,5-bisphosphate.";
RL   Photosyn. Res. 121:151-157(2014).
RN   [6]
RP   RUBISCO FOLDING AND ASSEMBLY, SUBUNIT, AND SUBCELLULAR LOCATION.
RC   STRAIN=ATCC 33912 / PCC 7942 / FACHB-805;
RX   PubMed=26237510; DOI=10.1038/nsmb.3062;
RA   Hauser T., Bhat J.Y., Milicic G., Wendler P., Hartl F.U., Bracher A.,
RA   Hayer-Hartl M.;
RT   "Structure and mechanism of the Rubisco-assembly chaperone Raf1.";
RL   Nat. Struct. Mol. Biol. 22:720-728(2015).
RN   [7]
RP   SUBCELLULAR LOCATION.
RC   STRAIN=ATCC 33912 / PCC 7942 / FACHB-805;
RX   PubMed=28616951; DOI=10.1039/c7nr02524f;
RA   Faulkner M., Rodriguez-Ramos J., Dykes G.F., Owen S.V., Casella S.,
RA   Simpson D.M., Beynon R.J., Liu L.N.;
RT   "Direct characterization of the native structure and mechanics of
RT   cyanobacterial carboxysomes.";
RL   Nanoscale 9:10662-10673(2017).
RN   [8]
RP   BIOTECHNOLOGY.
RC   STRAIN=ATCC 33912 / PCC 7942 / FACHB-805;
RX   PubMed=29922315; DOI=10.3389/fpls.2018.00739;
RA   Fang Y., Huang F., Faulkner M., Jiang Q., Dykes G.F., Yang M., Liu L.N.;
RT   "Engineering and Modulating Functional Cyanobacterial CO2-Fixing
RT   Organelles.";
RL   Front. Plant Sci. 9:739-739(2018).
RN   [9]
RP   SUBCELLULAR LOCATION, AND INDUCTION.
RC   STRAIN=ATCC 33912 / PCC 7942 / FACHB-805;
RX   PubMed=31048338; DOI=10.1105/tpc.18.00787;
RA   Sun Y., Wollman A.J.M., Huang F., Leake M.C., Liu L.N.;
RT   "Single-Organelle Quantification Reveals Stoichiometric and Structural
RT   Variability of Carboxysomes Dependent on the Environment.";
RL   Plant Cell 31:1648-1664(2019).
RN   [10]
RP   CARBOXYSOME ASSEMBLY PROCESS, AND SUBCELLULAR LOCATION.
RC   STRAIN=ATCC 33912 / PCC 7942 / FACHB-805;
RX   PubMed=32636267; DOI=10.1073/pnas.2007990117;
RA   Huang F., Kong W.W., Sun Y., Chen T., Dykes G.F., Jiang Y.L., Liu L.N.;
RT   "Rubisco accumulation factor 1 (Raf1) plays essential roles in mediating
RT   Rubisco assembly and carboxysome biogenesis.";
RL   Proc. Natl. Acad. Sci. U.S.A. 117:17418-17428(2020).
RN   [11] {ECO:0007744|PDB:6HBC}
RP   STRUCTURE BY ELECTRON MICROSCOPY (2.78 ANGSTROMS) IN COMPLEX WITH LARGE
RP   SUBUNIT AND CCMM35, FUNCTION, CATALYTIC ACTIVITY, AND SUBUNIT.
RC   STRAIN=ATCC 33912 / PCC 7942 / FACHB-805;
RX   PubMed=30675061; DOI=10.1038/s41586-019-0880-5;
RA   Wang H., Yan X., Aigner H., Bracher A., Nguyen N.D., Hee W.Y., Long B.M.,
RA   Price G.D., Hartl F.U., Hayer-Hartl M.;
RT   "Rubisco condensate formation by CcmM in beta-carboxysome biogenesis.";
RL   Nature 566:131-135(2019).
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.
CC       {ECO:0000255|HAMAP-Rule:MF_00859, ECO:0000269|PubMed:24585024,
CC       ECO:0000269|PubMed:30675061}.
CC   -!- FUNCTION: Beta-carboxysome assembly initiates when soluble RuBisCO
CC       aggregates is condensed into a liquid matrix in a pre-carboxysome by
CC       the RbcS-like domains of probably both CcmM58 and CcmM35. CcmN
CC       interacts with the N-terminus of CcmM58, and then recruits the CcmK2
CC       major shell protein via CcmN's encapsulation peptide. Shell formation
CC       requires CcmK proteins and CcmO. CcmL caps the otherwise elongated
CC       carboxysome. Once fully encapsulated carboxysomes are formed, they
CC       migrate within the cell probably via interactions with the
CC       cytoskeleton. {ECO:0000269|PubMed:24267892,
CC       ECO:0000269|PubMed:30675061}.
CC   -!- SUBUNIT: Heterohexadecamer of 8 large and 8 small subunits (Probable).
CC       The CcmM short form purifies from carboxysomes in complex with both
CC       RuBisCO subunits; a second complex with full-length CcmM and RuBisCO
CC       also includes carbonic anhydrase (CA, ccaA). RuBisCO-CcmM complexes are
CC       probably associated with the carboxysome shell (PubMed:17675289).
CC       Isolated reduced and oxidized SSUL1 binds holo-RuBisCO (RbcL(8)-
CC       RbcS(8)) but not either subunit octamer alone; RuBisCO has a higher
CC       affinity for reduced SSUL1 (PubMed:30675061).
CC       {ECO:0000269|PubMed:17675289, ECO:0000269|PubMed:30675061,
CC       ECO:0000305|PubMed:26237510, ECO:0000305|PubMed:30675061}.
CC   -!- SUBCELLULAR LOCATION: Carboxysome {ECO:0000255|HAMAP-Rule:MF_00859,
CC       ECO:0000269|PubMed:17675289, ECO:0000269|PubMed:22928045,
CC       ECO:0000269|PubMed:24585024, ECO:0000269|PubMed:28616951,
CC       ECO:0000269|PubMed:31048338, ECO:0000269|PubMed:32636267,
CC       ECO:0000305|PubMed:24267892}. Note=In the carboxysome RuBisCO is
CC       organized into a paracrystalline array (PubMed:28616951). This
CC       cyanobacterium makes beta-type carboxysomes (PubMed:22928045).
CC       {ECO:0000269|PubMed:22928045, ECO:0000269|PubMed:28616951}.
CC   -!- INDUCTION: Carboxysome size and components vary with growth conditions.
CC       When grown in ambient air at medium light (50 uE meter(-2) second(-1))
CC       there are 853 RuBisCO complexes (RbcL8S8) per carboxysome, the numbers
CC       decrease under low light and high CO(2), and increase under high light
CC       (at protein level). {ECO:0000269|PubMed:31048338}.
CC   -!- BIOTECHNOLOGY: Heterologous expression of 12 carboxysomal genes in
CC       E.coli (ccaA, ccmK2, ccmK3, ccmK4, ccmL, ccmM, ccmN, ccmO, ccmP, rbcL,
CC       rbcS, rbcX) leads to the formation of bodies that resemble
CC       carboxysomes, have densely packed paracrystalline arrays and RuBisCO
CC       activity. These structures open the door to generating carboxysomes in
CC       plant cells to increase their photosynthesis and productivity, as well
CC       as tailoring bacterial microcompartments to specific metabolic needs
CC       and molecule delivery. {ECO:0000269|PubMed:29922315}.
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:26237510, ECO:0000305|PubMed:32636267}.
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; CP000100; ABB57457.1; -; Genomic_DNA.
DR   PDB; 6HBC; EM; 2.78 A; D/E=1-111.
DR   PDB; 8BCM; EM; 2.15 A; D/E/K/L/M/N/O/P=1-111.
DR   PDBsum; 6HBC; -.
DR   PDBsum; 8BCM; -.
DR   AlphaFoldDB; Q31NB2; -.
DR   EMDB; EMD-0180; -.
DR   EMDB; EMD-15966; -.
DR   SMR; Q31NB2; -.
DR   STRING; 1140.Synpcc7942_1427; -.
DR   PaxDb; 1140-Synpcc7942_1427; -.
DR   KEGG; syf:Synpcc7942_1427; -.
DR   eggNOG; COG4451; Bacteria.
DR   HOGENOM; CLU_098114_2_0_3; -.
DR   BioCyc; SYNEL:SYNPCC7942_1427-MONOMER; -.
DR   SABIO-RK; Q31NB2; -.
DR   Proteomes; UP000889800; Chromosome.
DR   GO; GO:0031470; C:carboxysome; IDA:UniProtKB.
DR   GO; GO:0016984; F:ribulose-bisphosphate carboxylase activity; IEA:UniProtKB-UniRule.
DR   GO; GO:0009853; P:photorespiration; IEA:UniProtKB-KW.
DR   GO; GO:0019253; P:reductive pentose-phosphate cycle; IEA:UniProtKB-UniRule.
DR   CDD; cd03527; RuBisCO_small; 1.
DR   Gene3D; 3.30.190.10; Ribulose bisphosphate carboxylase, small subunit; 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; RIBULOSE BISPHOSPHATE CARBOXYLASE SMALL CHAIN 1, CHLOROPLASTIC; 1.
DR   Pfam; PF00101; RuBisCO_small; 1.
DR   SMART; SM00961; RuBisCO_small; 1.
DR   SUPFAM; SSF55239; RuBisCO, small subunit; 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..111
FT                   /note="Ribulose bisphosphate carboxylase small subunit"
FT                   /id="PRO_0000451248"
FT   TURN            15..17
FT                   /evidence="ECO:0007829|PDB:6HBC"
FT   HELIX           23..36
FT                   /evidence="ECO:0007829|PDB:6HBC"
FT   STRAND          39..46
FT                   /evidence="ECO:0007829|PDB:6HBC"
FT   STRAND          56..59
FT                   /evidence="ECO:0007829|PDB:6HBC"
FT   HELIX           69..81
FT                   /evidence="ECO:0007829|PDB:6HBC"
FT   STRAND          85..93
FT                   /evidence="ECO:0007829|PDB:6HBC"
FT   TURN            94..97
FT                   /evidence="ECO:0007829|PDB:6HBC"
FT   STRAND          98..106
FT                   /evidence="ECO:0007829|PDB:6HBC"
SQ   SEQUENCE   111 AA;  13333 MW;  F854F73FA70BD57B CRC64;
     MSMKTLPKER RFETFSYLPP LSDRQIAAQI EYMIEQGFHP LIEFNEHSNP EEFYWTMWKL
     PLFDCKSPQQ VLDEVRECRS EYGDCYIRVA GFDNIKQCQT VSFIVHRPGR Y
//