Database accession: MF7000854
Name: RbcX, mutant C103A (Thermosynechococcus elongatus)
PDB ID: 3q20
Experimental method: X-ray (1.71 Å)
Assembly: Homodimer
Source organism: Thermosynechococcus vestitus
Primary publication of the structure:
Tarnawski M, Krzywda S, Bialek W, Jaskolski M, Szczepaniak A
Structure of the RuBisCO chaperone RbcX from the thermophilic cyanobacterium Thermosynechococcus elongatus.
(2011) Acta Crystallogr. Sect. F Struct. Biol. Cryst. Commun. 67: 851-7
PMID: 21821880
Abstract:
The crystal structure of TeRbcX, a RuBisCO assembly chaperone from the cyanobacterium Thermosynechococcus elongatus, a thermophilic organism, has been determined at 1.7 Å resolution. TeRbcX has an unusual cysteine residue at position 103 that is not found in RbcX proteins from mesophilic organisms. Unlike wild-type TeRbcX, a mutant protein with Cys103 replaced by Ala (TeRbcX-C103A) could be readily crystallized. The structure revealed that the overall fold of the TeRbcX homodimer is similar to those of previously crystallized RbcX proteins. Normal-mode analysis suggested that TeRbcX might adopt an open or closed conformation through a hinge movement pivoted on a kink in two long α4 helices. This type of conformational transition is presumably connected to RbcL (the large RuBisCO subunit) binding during the chaperone function of the RuBisCO assembly.
Annotations from the GeneOntology database. Only terms that fit at least two of the interacting proteins are shown. Molecular function:
protein folding chaperone protein folding chaperone
Biological process:
carbon fixation carbon fixation
photosynthesis photosynthesis
ribulose bisphosphate carboxylase complex assembly ribulose bisphosphate carboxylase complex assembly
Cellular component:
carboxysome carboxysome
cytoplasm cytoplasm
Structural annotations of the participating protein chains.Entry contents: 2 distinct polypeptide molecules
Chains: A, B
Notes: All chains according to the most probable oligomerization state stored in PDBe were considered.
Number of unique protein segments: 1
Name: RuBisCO chaperone RbcX
Source organism: Thermosynechococcus vestitus
Length: 126 residues
Sequence:Sequence according to the corresponding UniProt protein segmentMDVKHIAKQTTKTLISYLTYQAVRTVIGQLAETDPPRSLWLHQFTSQESIQDGERYLEALFREQPDLGFRILTVREHLAEMVADYLPEMLRAGIQQANLQQRCQQLERMTQVSEANVENSNLETPE
UniProtKB AC: Q8DIS6 (positions: 1-114)
Coverage: 90%
Name: RuBisCO chaperone RbcX
Source organism: Thermosynechococcus vestitus
Length: 126 residues
Sequence:Sequence according to the corresponding UniProt protein segmentMDVKHIAKQTTKTLISYLTYQAVRTVIGQLAETDPPRSLWLHQFTSQESIQDGERYLEALFREQPDLGFRILTVREHLAEMVADYLPEMLRAGIQQANLQQRCQQLERMTQVSEANVENSNLETPE
UniProtKB AC: Q8DIS6 (positions: 2-107)
Coverage: 84%
Evidence demonstrating that the participating proteins are unstructured prior to the interaction and their folding is coupled to binding. Representative domain in related structures: Chaperonin-like RbcX
Evidence level: Indirect evidence
Evidence coverage: The full structure participates in mutual synergistic folding.
Complex Evidence:
There is no information on the stability/disoder of the monomeric forms. However, RbcX is a dimer in solution (PMID:17574029) and its biologically relevant form is the homodimer (a monomeric form with this fold is not known PMID:23295968, PMID:21821880). The structure is highly intertwined with the interface being extended and hydrophobic between the two four-helix-bundle cores and by the exchange of the C-terminal parts of the long a4 helices between the two subunits (PMID:21821880).
Chain A:
N/A
Chain B:
N/A
Surface and contacts features:
Structures from the PDB that contain the same number of proteins, and the proteins from the two structures show a sufficient degree of pairwise similarity, i.e. they belong to the same UniRef90 cluster (the full proteins exhibit at least 90% sequence identity) and convey roughly the same region to their respective interactions (the two regions from the two proteins share a minimum of 70% overlap). Download the CIF file (.cif)
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