ID   RBS1_MESCR              Reviewed;         182 AA.
AC   P16032;
DT   01-APR-1990, integrated into UniProtKB/Swiss-Prot.
DT   01-OCT-1994, sequence version 2.
DT   25-MAY-2022, entry version 100.
DE   RecName: Full=Ribulose bisphosphate carboxylase small subunit, chloroplastic 1 {ECO:0000255|HAMAP-Rule:MF_00860};
DE            Short=RuBisCO small subunit 1 {ECO:0000255|HAMAP-Rule:MF_00860};
DE   Flags: Precursor;
GN   Name=RBCS1 {ECO:0000255|HAMAP-Rule:MF_00860};
GN   Synonyms=RBC5 {ECO:0000303|PubMed:3627990}, RBCS,
GN   RBCS-1 {ECO:0000303|PubMed:8316216};
OS   Mesembryanthemum crystallinum (Common ice plant) (Cryophytum crystallinum).
OC   Eukaryota; Viridiplantae; Streptophyta; Embryophyta; Tracheophyta;
OC   Spermatophyta; Magnoliopsida; eudicotyledons; Gunneridae; Pentapetalae;
OC   Caryophyllales; Aizoaceae; Mesembryanthemum;
OC   Mesembryanthemum subgen. Cryophytum.
OX   NCBI_TaxID=3544;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA], AND INDUCTION.
RX   PubMed=8316216; DOI=10.1007/bf00276944;
RA   Derocher E.J., Quigley F., Mache R., Bohnert H.J.;
RT   "The six genes of the Rubisco small subunit multigene family from
RT   Mesembryanthemum crystallinum, a facultative CAM plant.";
RL   Mol. Gen. Genet. 239:450-462(1993).
RN   [2]
RP   NUCLEOTIDE SEQUENCE [MRNA].
RX   PubMed=3627990; DOI=10.1093/nar/15.15.6301;
RA   Derocher E.J., Ramage R.T., Michalowski C.B., Bohnert H.J.;
RT   "Nucleotide sequence of a cDNA encoding rbcS from the desert plant
RT   Mesembryanthemum crystallinum.";
RL   Nucleic Acids Res. 15:6301-6301(1987).
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. Both reactions occur simultaneously and in competition at
CC       the same active site. Although the small subunit is not catalytic it is
CC       essential for maximal activity. {ECO:0000255|HAMAP-Rule:MF_00860}.
CC   -!- SUBUNIT: Heterohexadecamer of 8 large and 8 small subunits.
CC       {ECO:0000255|HAMAP-Rule:MF_00860}.
CC   -!- SUBCELLULAR LOCATION: Plastid, chloroplast {ECO:0000255|HAMAP-
CC       Rule:MF_00860}.
CC   -!- INDUCTION: The most highly expressed of the 6 small subunit genes.
CC       {ECO:0000269|PubMed:8316216}.
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_00860}.
CC   -!- SIMILARITY: Belongs to the RuBisCO small chain family.
CC       {ECO:0000255|HAMAP-Rule:MF_00860}.
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DR   EMBL; L10212; AAA03693.1; -; mRNA.
DR   EMBL; M31640; AAA33035.1; -; mRNA.
DR   PIR; A29118; RKIXS.
DR   PIR; S35247; S35247.
DR   AlphaFoldDB; P16032; -.
DR   SMR; P16032; -.
DR   PRIDE; P16032; -.
DR   GO; GO:0009507; C:chloroplast; 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; IPR024680; RuBisCO_ssu_N.
DR   InterPro; IPR036385; RuBisCO_ssu_sf.
DR   PANTHER; PTHR31262; PTHR31262; 1.
DR   Pfam; PF12338; RbcS; 1.
DR   Pfam; PF00101; RuBisCO_small; 1.
DR   PRINTS; PR00152; RUBISCOSMALL.
DR   SMART; SM00961; RuBisCO_small; 1.
DR   SUPFAM; SSF55239; SSF55239; 1.
PE   2: Evidence at transcript level;
KW   Calvin cycle; Carbon dioxide fixation; Chloroplast; Photorespiration;
KW   Photosynthesis; Plastid; Transit peptide.
FT   TRANSIT         1..56
FT                   /note="Chloroplast"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00860"
FT   CHAIN           57..182
FT                   /note="Ribulose bisphosphate carboxylase small subunit,
FT                   chloroplastic 1"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00860"
FT                   /id="PRO_0000031527"
FT   CONFLICT        25
FT                   /note="A -> V (in Ref. 2; AAA33035)"
FT                   /evidence="ECO:0000305"
FT   CONFLICT        145
FT                   /note="E -> R (in Ref. 2; AAA33035)"
FT                   /evidence="ECO:0000305"
SQ   SEQUENCE   182 AA;  20276 MW;  7AB023654AF05665 CRC64;
     MASSMVSSAA VATVNRTPAQ ASMVAPFNGL KSVAAFPVTK KNNDITSVAT NGGRVQCMQV
     WPPLGKKKFE TLSYLPPLSE ESLMKEVQYL LNNGWVPCLE FEPTHGFVYR EHGNTPGYYD
     GRYWTMWKLP MFGCTDPSQV VAELEEAKKA YPEAFIRIIG FDNVRQVQCI SFIAYKPASY
     DA