ID   RBS_CHAMQ               Reviewed;          20 AA.
AC   C0HLR0;
DT   17-JUN-2020, integrated into UniProtKB/Swiss-Prot.
DT   17-JUN-2020, sequence version 1.
DT   25-MAY-2022, entry version 7.
DE   RecName: Full=Ribulose bisphosphate carboxylase small subunit {ECO:0000255|HAMAP-Rule:MF_00859, ECO:0000303|PubMed:23291769};
DE            Short=RuBisCO small subunit {ECO:0000255|HAMAP-Rule:MF_00859};
DE   Flags: Fragment;
GN   Name=rbcS {ECO:0000255|HAMAP-Rule:MF_00859};
OS   Chattonella marina var. antiqua (Red tide flagellate) (Chattonella
OS   antiqua).
OC   Eukaryota; Sar; Stramenopiles; Ochrophyta; Raphidophyceae; Chattonellales;
OC   Chattonellaceae; Chattonella.
OX   NCBI_TaxID=859642;
RN   [1] {ECO:0000305}
RP   PROTEIN SEQUENCE.
RC   STRAIN=NIES-1 {ECO:0000303|PubMed:23291769};
RX   PubMed=23291769; DOI=10.1271/bbb.120543;
RA   Qiu X., Shimasaki Y., Tsuyama M., Yamada T., Kuwahara R., Kawaguchi M.,
RA   Honda M., Gunjikake H., Tasmin R., Shimizu M., Sato Y., Kato-Unoki Y.,
RA   Nakashima T., Matsubara T., Yamasaki Y., Ichinose H., Wariishi H.,
RA   Honjo T., Oshima Y.;
RT   "Growth-phase dependent variation in photosynthetic activity and cellular
RT   protein expression profile in the harmful raphidophyte Chattonella
RT   antiqua.";
RL   Biosci. Biotechnol. Biochem. 77:46-52(2013).
RN   [2] {ECO:0000305}
RP   PROTEIN SEQUENCE, AND INDUCTION.
RC   STRAIN=NIES-1 {ECO:0000303|Ref.2};
RX   DOI=10.1016/j.jembe.2020.151361;
RA   Qiu X., Mukai K., Shimasaki Y., Wu M., Chen C., Lu Y., Ichinose H.,
RA   Nakashima T., Kato-Unoki Y., Oshima Y.;
RT   "Diurnal variations in expression of photosynthesis-related proteins in the
RT   harmful Raphidophyceae Chattonella marina var. antiqua.";
RL   J. Exp. Mar. Biol. Ecol. 527:0-0(2020).
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   -!- INDUCTION: Expressed at a constant level during a 12 hours light:12
CC       hours dark diurnal cycle (at protein level). {ECO:0000269|Ref.2}.
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   -!- MISCELLANEOUS: In this alga, in contrast to plants, the small subunit
CC       is encoded in the chloroplast. {ECO:0000305}.
CC   -!- SIMILARITY: Belongs to the RuBisCO small chain family.
CC       {ECO:0000255|HAMAP-Rule:MF_00859}.
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DR   AlphaFoldDB; C0HLR0; -.
DR   GO; GO:0009507; C:chloroplast; IEA:UniProtKB-SubCell.
DR   GO; GO:0019253; P:reductive pentose-phosphate cycle; IEA:UniProtKB-KW.
DR   Gene3D; 3.30.190.10; -; 1.
DR   InterPro; IPR036385; RuBisCO_ssu_sf.
DR   SUPFAM; SSF55239; SSF55239; 1.
PE   1: Evidence at protein level;
KW   Calvin cycle; Carbon dioxide fixation; Chloroplast;
KW   Direct protein sequencing; Photorespiration; Photosynthesis; Plastid.
FT   CHAIN           1..>20
FT                   /note="Ribulose bisphosphate carboxylase small subunit"
FT                   /id="PRO_0000450209"
FT   NON_TER         20
FT                   /evidence="ECO:0000303|PubMed:23291769"
SQ   SEQUENCE   20 AA;  2254 MW;  8D17B605020FF5F5 CRC64;
     MRLTQGAFSY LPDLTDAQII