ID   RBS4_MESCR              Reviewed;         183 AA.
AC   Q08184;
DT   01-OCT-1994, integrated into UniProtKB/Swiss-Prot.
DT   01-OCT-1994, sequence version 1.
DT   25-MAY-2022, entry version 92.
DE   RecName: Full=Ribulose bisphosphate carboxylase small subunit, chloroplastic 4 {ECO:0000255|HAMAP-Rule:MF_00860};
DE            Short=RuBisCO small subunit 4 {ECO:0000255|HAMAP-Rule:MF_00860};
DE   Flags: Precursor;
GN   Name=RBCS4 {ECO:0000255|HAMAP-Rule:MF_00860};
GN   Synonyms=RBCS-4 {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, 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.
RX   PubMed=16668083; DOI=10.1104/pp.95.3.976;
RA   Derocher E.J., Michalowski C.B., Bohnert H.J.;
RT   "cDNA sequences for transcripts of the ribulose-1,5-bisphosphate
RT   carboxylase/oxygenase small subunit gene family of Mesembryanthemum
RT   crystallinum.";
RL   Plant Physiol. 95:976-978(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. 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: Expressed at intermediate levels.
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; L10215; AAA03696.1; -; Unassigned_DNA.
DR   EMBL; M38318; AAA33038.1; -; mRNA.
DR   PIR; S35244; S35244.
DR   AlphaFoldDB; Q08184; -.
DR   SMR; Q08184; -.
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..57
FT                   /note="Chloroplast"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00860"
FT   CHAIN           58..183
FT                   /note="Ribulose bisphosphate carboxylase small subunit,
FT                   chloroplastic 4"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00860"
FT                   /id="PRO_0000031530"
SQ   SEQUENCE   183 AA;  20312 MW;  E1AE7D11EB6D605F CRC64;
     MASSLMSNAA TTMAAATTTA QANMVAPFNG LKSISAFPVT RKNNDITSVA SNGGRVQCMQ
     VWPPLGMKKF ETLSYLPPLS EESLLKEVQY LLNNGWVPCL EFEPTHGFVY REHGNTPGYY
     DGRYWTMWKL PMFGCTDPSQ VVAELEEAKK AYPEAFIRII GFDNVRQVQC VSFIAYKPAS
     YGA