RBS_GALSU
ID RBS_GALSU Reviewed; 138 AA.
AC P23756;
DT 01-NOV-1991, integrated into UniProtKB/Swiss-Prot.
DT 01-NOV-1991, sequence version 1.
DT 25-MAY-2022, entry version 99.
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 Galdieria sulphuraria (Red alga).
OG Plastid; Chloroplast.
OC Eukaryota; Rhodophyta; Bangiophyceae; Cyanidiales; Cyanidiaceae; Galdieria.
OX NCBI_TaxID=130081;
RN [1]
RP NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RC STRAIN=14-1-1 / Isolate 107.79/Goettingen;
RX PubMed=2274041; DOI=10.1007/bf00633849;
RA Valentin K.-U., Zetsche K.;
RT "Structure of the Rubisco operon from the unicellular red alga Cyanidium
RT caldarium: evidence for a polyphyletic origin of the plastids.";
RL Mol. Gen. Genet. 222:425-430(1990).
RN [2]
RP NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RC STRAIN=UTEX 2393;
RA Whitney S.M., Andrews J.;
RL Submitted (FEB-2000) to the EMBL/GenBank/DDBJ databases.
RN [3] {ECO:0007744|PDB:4F0H, ECO:0007744|PDB:4F0K, ECO:0007744|PDB:4F0M}
RP X-RAY CRYSTALLOGRAPHY (1.96 ANGSTROMS) OF UNACTIVATED HOLOENZYME IN COMPLEX
RP WITH O2 OR CO2 AND MAGNESIUM, FUNCTION, AND SUBUNIT.
RX PubMed=23112176; DOI=10.1073/pnas.1210754109;
RA Stec B.;
RT "Structural mechanism of RuBisCO activation by carbamylation of the active
RT site lysine.";
RL Proc. Natl. Acad. Sci. U.S.A. 109:18785-18790(2012).
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 Carbon dioxide and oxygen bind in the same pocket of the enzyme in a
CC similar manner (PubMed:23112176). {ECO:0000255|HAMAP-Rule:MF_00859,
CC ECO:0000269|PubMed:23112176, ECO:0000305|PubMed:23112176}.
CC -!- SUBUNIT: Heterohexadecamer of 8 large and 8 small subunits.
CC {ECO:0000255|HAMAP-Rule:MF_00859, ECO:0000269|PubMed:23112176}.
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: Although originally identified as Cyanidium caldarium,
CC these sequences derive from Galdieria sulphuraria. {ECO:0000305}.
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, ECO:0000269|PubMed:23112176}.
CC -!- SIMILARITY: Belongs to the RuBisCO small chain family.
CC {ECO:0000255|HAMAP-Rule:MF_00859}.
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DR EMBL; X55524; CAA39141.2; -; Genomic_DNA.
DR EMBL; AF233069; AAF81682.1; -; Genomic_DNA.
DR PDB; 4F0H; X-ray; 1.96 A; B=1-138.
DR PDB; 4F0K; X-ray; 2.05 A; B=1-138.
DR PDB; 4F0M; X-ray; 2.25 A; B=1-138.
DR PDBsum; 4F0H; -.
DR PDBsum; 4F0K; -.
DR PDBsum; 4F0M; -.
DR AlphaFoldDB; P23756; -.
DR SMR; P23756; -.
DR DIP; DIP-60090N; -.
DR IntAct; P23756; 1.
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 1: Evidence at protein level;
KW 3D-structure; Calvin cycle; Carbon dioxide fixation; Chloroplast;
KW Photorespiration; Photosynthesis; Plastid.
FT CHAIN 1..138
FT /note="Ribulose bisphosphate carboxylase small subunit"
FT /id="PRO_0000198598"
FT TURN 7..10
FT /evidence="ECO:0007829|PDB:4F0H"
FT HELIX 16..28
FT /evidence="ECO:0007829|PDB:4F0H"
FT STRAND 32..39
FT /evidence="ECO:0007829|PDB:4F0H"
FT STRAND 49..52
FT /evidence="ECO:0007829|PDB:4F0H"
FT HELIX 61..74
FT /evidence="ECO:0007829|PDB:4F0H"
FT TURN 75..77
FT /evidence="ECO:0007829|PDB:4F0H"
FT STRAND 78..86
FT /evidence="ECO:0007829|PDB:4F0H"
FT TURN 89..91
FT /evidence="ECO:0007829|PDB:4F0H"
FT STRAND 93..101
FT /evidence="ECO:0007829|PDB:4F0H"
FT STRAND 109..115
FT /evidence="ECO:0007829|PDB:4F0H"
FT STRAND 121..127
FT /evidence="ECO:0007829|PDB:4F0H"
FT HELIX 128..131
FT /evidence="ECO:0007829|PDB:4F0H"
FT HELIX 134..136
FT /evidence="ECO:0007829|PDB:4F0H"
SQ SEQUENCE 138 AA; 16206 MW; 5E946BA51DAFAEC2 CRC64;
MRITQGTFSF LPDLTDEQIK KQIDYMISKK LAIGIEYTND IHPRNSFWEM WGLPLFEVTD
PAPVLFEINA CRKAKSNFYI KVVGFSSERG IESTIISFIV NRPKHEPGFN LIRQEDKSRS
IKYSIQAYET YKPEDQRY
