UniProt functional annotation for P04716



	UniProt functional annotation for P04716

UniProt code: P04716.

Organism: Synechococcus sp. (strain ATCC 27144 / PCC 6301 / SAUG 1402/1) (Anacystis nidulans).

Taxonomy: Bacteria; Cyanobacteria; Synechococcales; Synechococcaceae; Synechococcus.

Function: RuBisCO catalyzes two reactions: the carboxylation of D- ribulose 1,5-bisphosphate, the primary event in carbon dioxide fixation, as well as the oxidative fragmentation of the pentose substrate. Both reactions occur simultaneously and in competition at the same active site (PubMed:7922027, PubMed:9882445). The small subunit displaces RbcX2 from the RbcL8-(RbcX2)8 assembly intermediate, and stabilizes an RbcL loop ('Thr-64-Leu-70') in a catalytically competent conformation (PubMed:21765418). {ECO:0000269|PubMed:21765418, ECO:0000269|PubMed:7922027, ECO:0000269|PubMed:9882445}.

Biophysicochemical properties: Kinetic parameters: KM=39 uM for ribulose 1,5-bisphosphate {ECO:0000269|PubMed:9882445}; KM=173 uM for CO(2) {ECO:0000269|PubMed:9882445}; Vmax=2.5 umol/min/mg enzyme with CO(2) as substrate {ECO:0000269|PubMed:9882445}; Note=The CO(2)/O(2) specificity factor (tau) is 39. {ECO:0000269|PubMed:9882445};

Subunit: Heterohexadecamer of 8 large and 8 small subunits (PubMed:17574029, PubMed:21765418, PubMed:8245022, PubMed:7922027). Displaces RbcX2 from the RbcL8-(RbcX2)8 assembly intermediate (Probable) (PubMed:21765418). {ECO:0000269|PubMed:17574029, ECO:0000269|PubMed:21765418, ECO:0000269|PubMed:7922027, ECO:0000269|PubMed:8245022}.

Subcellular location: Carboxysome {ECO:0000255|HAMAP-Rule:MF_00859}. Note=In the carboxysome RuBisCO is organized into a paracrystalline array (By similarity). This cyanobacterium makes beta-type carboxysomes (Probable). {ECO:0000250|UniProtKB:Q31NB2, ECO:0000305}.

Miscellaneous: The basic functional RuBisCO is composed of a large chain homodimer in a 'head-to-tail' conformation. In form I RuBisCO this homodimer is arranged in a barrel-like tetramer with the small subunits forming a tetrameric 'cap' on each end of the 'barrel'. {ECO:0000255|HAMAP-Rule:MF_00859, ECO:0000269|PubMed:17574029, ECO:0000269|PubMed:7922027, ECO:0000269|PubMed:8245022}.

Similarity: Belongs to the RuBisCO small chain family. {ECO:0000255|HAMAP-Rule:MF_00859}.

Annotations taken from UniProtKB at the EBI.


Organism:		Synechococcus sp. (strain ATCC 27144 / PCC 6301 / SAUG 1402/1) (Anacystis nidulans).
Taxonomy:		Bacteria; Cyanobacteria; Synechococcales; Synechococcaceae; Synechococcus.



Function:		RuBisCO catalyzes two reactions: the carboxylation of D- ribulose 1,5-bisphosphate, the primary event in carbon dioxide fixation, as well as the oxidative fragmentation of the pentose substrate. Both reactions occur simultaneously and in competition at the same active site (PubMed:7922027, PubMed:9882445). The small subunit displaces RbcX2 from the RbcL8-(RbcX2)8 assembly intermediate, and stabilizes an RbcL loop ('Thr-64-Leu-70') in a catalytically competent conformation (PubMed:21765418). {ECO:0000269\|PubMed:21765418, ECO:0000269\|PubMed:7922027, ECO:0000269\|PubMed:9882445}.


Biophysicochemical properties:		Kinetic parameters: KM=39 uM for ribulose 1,5-bisphosphate {ECO:0000269\|PubMed:9882445}; KM=173 uM for CO(2) {ECO:0000269\|PubMed:9882445}; Vmax=2.5 umol/min/mg enzyme with CO(2) as substrate {ECO:0000269\|PubMed:9882445}; Note=The CO(2)/O(2) specificity factor (tau) is 39. {ECO:0000269\|PubMed:9882445};
Subunit:		Heterohexadecamer of 8 large and 8 small subunits (PubMed:17574029, PubMed:21765418, PubMed:8245022, PubMed:7922027). Displaces RbcX2 from the RbcL8-(RbcX2)8 assembly intermediate (Probable) (PubMed:21765418). {ECO:0000269\|PubMed:17574029, ECO:0000269\|PubMed:21765418, ECO:0000269\|PubMed:7922027, ECO:0000269\|PubMed:8245022}.
Subcellular location:		Carboxysome {ECO:0000255\|HAMAP-Rule:MF_00859}. Note=In the carboxysome RuBisCO is organized into a paracrystalline array (By similarity). This cyanobacterium makes beta-type carboxysomes (Probable). {ECO:0000250\|UniProtKB:Q31NB2, ECO:0000305}.
Miscellaneous:		The basic functional RuBisCO is composed of a large chain homodimer in a 'head-to-tail' conformation. In form I RuBisCO this homodimer is arranged in a barrel-like tetramer with the small subunits forming a tetrameric 'cap' on each end of the 'barrel'. {ECO:0000255\|HAMAP-Rule:MF_00859, ECO:0000269\|PubMed:17574029, ECO:0000269\|PubMed:7922027, ECO:0000269\|PubMed:8245022}.
Similarity:		Belongs to the RuBisCO small chain family. {ECO:0000255\|HAMAP-Rule:MF_00859}.