ID   RBS_ECTSI               Reviewed;         139 AA.
AC   P24395;
DT   01-MAR-1992, integrated into UniProtKB/Swiss-Prot.
DT   01-MAR-1992, sequence version 1.
DT   25-MAY-2022, entry version 95.
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=rbcS {ECO:0000255|HAMAP-Rule:MF_00859};
OS   Ectocarpus siliculosus (Brown alga) (Conferva siliculosa).
OG   Plastid; Chloroplast.
OC   Eukaryota; Sar; Stramenopiles; Ochrophyta; PX clade; Phaeophyceae;
OC   Ectocarpales; Ectocarpaceae; Ectocarpus.
OX   NCBI_TaxID=2880;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RC   STRAIN=Dillwyn / Lyngbye;
RX   PubMed=2102375; DOI=10.1007/bf00017832;
RA   Valentin K.-U., Zetsche K.;
RT   "Rubisco genes indicate a close phylogenetic relation between the plastids
RT   of Chromophyta and Rhodophyta.";
RL   Plant Mol. Biol. 15:575-584(1990).
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}.
CC   -!- SUBUNIT: Heterohexadecamer of 8 large and 8 small subunits.
CC       {ECO:0000255|HAMAP-Rule:MF_00859}.
CC   -!- SUBCELLULAR LOCATION: Plastid, chloroplast {ECO:0000255|HAMAP-
CC       Rule:MF_00859}.
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; X52503; CAA36744.1; -; Genomic_DNA.
DR   PIR; S13124; RKAUS.
DR   AlphaFoldDB; P24395; -.
DR   SMR; P24395; -.
DR   eggNOG; ENOG502QTPB; Eukaryota.
DR   GO; GO:0009507; C:chloroplast; IEA:UniProtKB-SubCell.
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   3: Inferred from homology;
KW   Calvin cycle; Carbon dioxide fixation; Chloroplast; Photorespiration;
KW   Photosynthesis; Plastid.
FT   CHAIN           1..139
FT                   /note="Ribulose bisphosphate carboxylase small subunit"
FT                   /id="PRO_0000198597"
SQ   SEQUENCE   139 AA;  15938 MW;  E316D7803358702D CRC64;
     MRVTQGCFSF LPDLSDDQIK QQVSYAMSKG WAVSVEWTDD PHPRNSYWEL WGLPLFDVKD
     PAAVMYELAE CRKVNPEGYI KINAFDASIG TESCVMSFIV QRPITEPGFY LERNEIHGRN
     IQYTISSYAV QARPSGDRY