RBCX_SYNE7
ID RBCX_SYNE7 Reviewed; 152 AA.
AC Q31N04;
DT 02-DEC-2020, integrated into UniProtKB/Swiss-Prot.
DT 06-DEC-2005, sequence version 1.
DT 03-AUG-2022, entry version 66.
DE RecName: Full=RuBisCO chaperone RbcX {ECO:0000255|HAMAP-Rule:MF_00855, ECO:0000303|PubMed:17071623};
GN Name=rbcX {ECO:0000255|HAMAP-Rule:MF_00855, ECO:0000303|PubMed:17071623};
GN OrderedLocusNames=Synpcc7942_1535;
OS Synechococcus elongatus (strain PCC 7942 / FACHB-805) (Anacystis nidulans
OS R2).
OC Bacteria; Cyanobacteria; Synechococcales; Synechococcaceae; Synechococcus.
OX NCBI_TaxID=1140;
RN [1]
RP NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC STRAIN=PCC 7942 / FACHB-805;
RG US DOE Joint Genome Institute;
RA Copeland A., Lucas S., Lapidus A., Barry K., Detter J.C., Glavina T.,
RA Hammon N., Israni S., Pitluck S., Schmutz J., Larimer F., Land M.,
RA Kyrpides N., Lykidis A., Richardson P.;
RT "Complete sequence of chromosome 1 of Synechococcus elongatus PCC 7942.";
RL Submitted (AUG-2005) to the EMBL/GenBank/DDBJ databases.
RN [2]
RP FUNCTION UPON EXPRESSION IN E.COLI, INDUCTION, AND DISRUPTION PHENOTYPE.
RC STRAIN=PCC 7942 / FACHB-805;
RX PubMed=17071623; DOI=10.1093/pcp/pcl028;
RA Emlyn-Jones D., Woodger F.J., Price G.D., Whitney S.M.;
RT "RbcX can function as a rubisco chaperonin, but is non-essential in
RT Synechococcus PCC7942.";
RL Plant Cell Physiol. 47:1630-1640(2006).
RN [3]
RP BIOTECHNOLOGY.
RC STRAIN=PCC 7942 / FACHB-805;
RX PubMed=29922315; DOI=10.3389/fpls.2018.00739;
RA Fang Y., Huang F., Faulkner M., Jiang Q., Dykes G.F., Yang M., Liu L.N.;
RT "Engineering and Modulating Functional Cyanobacterial CO2-Fixing
RT Organelles.";
RL Front. Plant Sci. 9:739-739(2018).
RN [4]
RP FUNCTION, SUBCELLULAR LOCATION, AND DISRUPTION PHENOTYPE.
RC STRAIN=PCC 7942 / FACHB-805;
RX PubMed=30389782; DOI=10.1104/pp.18.01217;
RA Huang F., Vasieva O., Sun Y., Faulkner M., Dykes G.F., Zhao Z., Liu L.N.;
RT "Roles of RbcX in Carboxysome Biosynthesis in the Cyanobacterium
RT Synechococcus elongatus PCC7942.";
RL Plant Physiol. 179:184-194(2019).
RN [5]
RP SUBCELLULAR LOCATION, AND INDUCTION.
RC STRAIN=PCC 7942 / FACHB-805;
RX PubMed=31048338; DOI=10.1105/tpc.18.00787;
RA Sun Y., Wollman A.J.M., Huang F., Leake M.C., Liu L.N.;
RT "Single-Organelle Quantification Reveals Stoichiometric and Structural
RT Variability of Carboxysomes Dependent on the Environment.";
RL Plant Cell 31:1648-1664(2019).
RN [6]
RP DISRUPTION PHENOTYPE.
RC STRAIN=PCC 7942 / FACHB-805;
RX PubMed=32636267; DOI=10.1073/pnas.2007990117;
RA Huang F., Kong W.W., Sun Y., Chen T., Dykes G.F., Jiang Y.L., Liu L.N.;
RT "Rubisco accumulation factor 1 (Raf1) plays essential roles in mediating
RT Rubisco assembly and carboxysome biogenesis.";
RL Proc. Natl. Acad. Sci. U.S.A. 117:17418-17428(2020).
CC -!- FUNCTION: An RbcL-specific chaperone. The central cleft of the RbcX
CC homodimer (RbcX2) binds the C-terminus of an RbcL monomer, stabilizing
CC the C-terminus and probably preventing its reassociation with
CC chaperonin GroEL-ES. At the same time the peripheral region of RbcX2
CC binds a second RbcL monomer, bridging the RbcL homodimers in the
CC correct orientation. The RbcX2(2)-bound RbcL dimers then assemble into
CC the RbcL8 core (RbcL8-(RbcX2)8). RbcS binding triggers the release of
CC RbcX2. {ECO:0000255|HAMAP-Rule:MF_00855}.
CC -!- FUNCTION: Colocalizes with RuBisCO throughout carboxysome formation,
CC suggesting it plays a role in caboxysome biogenesis; may also be
CC involved in RuBisCO holoenzyme stabilization or adjusting its packing
CC in carboxysomes. {ECO:0000269|PubMed:30389782}.
CC -!- FUNCTION: Improves functional assembly of RuBisCO upon coexpression in
CC E.coli with the large and small subunits of RuBisCO (rbcL and rbcS),
CC however it is not essential in vivo (PubMed:17071623).
CC {ECO:0000269|PubMed:17071623}.
CC -!- SUBUNIT: Homodimer. Interacts with the exposed C-terminal peptide of
CC RbcL via its central cleft, contacts a second RbcL monomer via its
CC peripheral polar surface. {ECO:0000255|HAMAP-Rule:MF_00855}.
CC -!- SUBCELLULAR LOCATION: Carboxysome {ECO:0000255|HAMAP-Rule:MF_00855,
CC ECO:0000269|PubMed:30389782, ECO:0000269|PubMed:31048338}. Cytoplasm
CC {ECO:0000255|HAMAP-Rule:MF_00855, ECO:0000269|PubMed:30389782}.
CC Note=Most protein is cytoplasmic, but some is in the carboxysome.
CC {ECO:0000255|HAMAP-Rule:MF_00855}.
CC -!- INDUCTION: Transcribed at very low levels under several growth
CC conditions; in this paper protein was never detected (PubMed:17071623).
CC Carboxysome size and components vary with growth conditions. When grown
CC in ambient air at medium light (50 uE meter(-2) second(-1)) there are
CC 40 units of this protein per carboxysome, which remain constant under
CC all conditions tested (at protein level) (PubMed:31048338).
CC {ECO:0000269|PubMed:17071623, ECO:0000269|PubMed:31048338}.
CC -!- DOMAIN: The homodimer has 2 functional domains, a central cleft
CC essential for production of soluble RbcL in which the RbcL peptide
CC binds, and a polar surface which plays a role in correct RbcL subunit
CC arrangement. {ECO:0000255|HAMAP-Rule:MF_00855}.
CC -!- DISRUPTION PHENOTYPE: Non-essential, no visible growth phenotype in
CC ambient air or 2% CO(2), no change in RuBisCO assembly or activity
CC (PubMed:17071623). Non-essential, has a reduced growth rate in 5%
CC CO(2), about 2-fold higher amounts of RbcL accumulate. Cells have
CC fewer, larger carboxysomes, their positioning is often abnormal
CC (PubMed:30389782). A double raf1-rbcX deletion partially recovers
CC carboxysome formation compared to the raf1 deletion alone
CC (PubMed:32636267). {ECO:0000269|PubMed:17071623,
CC ECO:0000269|PubMed:30389782, ECO:0000269|PubMed:32636267}.
CC -!- BIOTECHNOLOGY: Heterologous expression of 12 carboxysomal genes in
CC E.coli (ccaA, ccmK2, ccmK3, ccmK4, ccmL, ccmM, ccmN, ccmO, ccmP, rbcL,
CC rbcS, rbcX) leads to the formation of bodies that resemble
CC carboxysomes, have densely packed paracrystalline arrays and RuBisCO
CC activity. These structures open the door to generating carboxysomes in
CC plant cells to increase their photosynthesis and productivity, as well
CC as tailoring bacterial microcompartments to specific metabolic needs
CC and molecule delivery. The absence of ccaA, ccmK3, ccmK4, ccmP and rbcX
CC leads to less active RuBisCO. {ECO:0000269|PubMed:29922315}.
CC -!- MISCELLANEOUS: Unlike most cyanobacteria, in PCC 7942 this gene is not
CC encoded in the rbcL-rbcS operon. {ECO:0000269|Ref.1}.
CC -!- SIMILARITY: Belongs to the RbcX family. {ECO:0000255|HAMAP-
CC Rule:MF_00855}.
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DR EMBL; CP000100; ABB57565.1; -; Genomic_DNA.
DR AlphaFoldDB; Q31N04; -.
DR SMR; Q31N04; -.
DR STRING; 1140.Synpcc7942_1535; -.
DR PRIDE; Q31N04; -.
DR EnsemblBacteria; ABB57565; ABB57565; Synpcc7942_1535.
DR KEGG; syf:Synpcc7942_1535; -.
DR eggNOG; ENOG50315SX; Bacteria.
DR HOGENOM; CLU_129346_0_0_3; -.
DR OMA; DYLPEMV; -.
DR BioCyc; SYNEL:SYNPCC7942_1535-MON; -.
DR GO; GO:0031470; C:carboxysome; IDA:UniProtKB.
DR GO; GO:0005737; C:cytoplasm; IDA:UniProtKB.
DR GO; GO:0044183; F:protein folding chaperone; IEA:InterPro.
DR GO; GO:0015977; P:carbon fixation; IEA:UniProtKB-KW.
DR GO; GO:0015979; P:photosynthesis; IEA:UniProtKB-KW.
DR GO; GO:0110102; P:ribulose bisphosphate carboxylase complex assembly; IEA:InterPro.
DR Gene3D; 1.10.1200.210; -; 1.
DR HAMAP; MF_00855; RbcX; 1.
DR InterPro; IPR038052; Chaperonin_RbcX_sf.
DR InterPro; IPR003435; Chaperonin_RcbX.
DR InterPro; IPR046381; RbcX.
DR PANTHER; PTHR33791; PTHR33791; 1.
DR Pfam; PF02341; RbcX; 1.
DR SUPFAM; SSF158615; SSF158615; 1.
PE 1: Evidence at protein level;
KW Bacterial microcompartment; Carbon dioxide fixation; Carboxysome;
KW Chaperone; Cytoplasm; Photosynthesis.
FT CHAIN 1..152
FT /note="RuBisCO chaperone RbcX"
FT /id="PRO_0000451300"
FT REGION 121..152
FT /note="Disordered"
FT /evidence="ECO:0000256|SAM:MobiDB-lite"
FT COMPBIAS 132..152
FT /note="Polar residues"
FT /evidence="ECO:0000256|SAM:MobiDB-lite"
SQ SEQUENCE 152 AA; 16982 MW; FB69BE6149B4016C CRC64;
MASTQRAKPM EMPRISRDTA RMLVNYLTYQ AVCVIRDQLA ETNPAGAYRL QVFSAEFSFQ
DGEAYLAALL NHDRELGLRV MTVREHLAEH ILDYLPEMTI AQIQEANINH RRALLERLTG
LGAEPSLPET EVSDRPSDSA TPDDASNASH AD
