ID   RBS_PYLLI               Reviewed;         139 AA.
AC   P23652;
DT   01-NOV-1991, integrated into UniProtKB/Swiss-Prot.
DT   01-NOV-1991, sequence version 1.
DT   25-MAY-2022, entry version 96.
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   Pylaiella littoralis (Seaweed) (Conferva littoralis).
OG   Plastid; Chloroplast.
OC   Eukaryota; Sar; Stramenopiles; Ochrophyta; PX clade; Phaeophyceae;
OC   Ectocarpales; Acinetosporaceae; Pylaiella.
OX   NCBI_TaxID=2885;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=2103450; DOI=10.1007/bf00036916;
RA   Assali N.E., Mache R., Loiseaux-De Goer S.;
RT   "Evidence for a composite phylogenetic origin of the plastid genome of the
RT   brown alga Pylaiella littoralis (L.) Kjellm.";
RL   Plant Mol. Biol. 15:307-315(1990).
RN   [2]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=1840691; DOI=10.1007/bf00037066;
RA   Assali N.E., Martin W.F., Sommerville C.C., Loiseaux-De Goer S.;
RT   "Evolution of the Rubisco operon from prokaryotes to algae: structure and
RT   analysis of the rbcS gene of the brown alga Pylaiella littoralis.";
RL   Plant Mol. Biol. 17:853-863(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 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: In this alga, in contrast to plants, the small subunit
CC       is encoded in the chloroplast.
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; X55372; CAA39052.1; -; Genomic_DNA.
DR   PIR; S17764; RKPFSL.
DR   AlphaFoldDB; P23652; -.
DR   SMR; P23652; -.
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_0000198605"
SQ   SEQUENCE   139 AA;  15897 MW;  075DC3800915DDC5 CRC64;
     MRVTQGCFSF LPDLSDEQIK LQVGYAMSKG WAVSVEWTDD PHPRNSYWEL WGLPLFDVKD
     PAAVMYELAE CRKVNPEGYI KINAFDASIG TESCVMSFIV QRPINEPGFY LERNEVQGRN
     IQYTISSYAV QARPSGDRY