PDBsum entry 3o7o

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protein metals Protein-protein interface(s) links
Hydrolase PDB id
Protein chains
264 a.a. *
_BR ×7
Waters ×72
* Residue conservation analysis
PDB id:
Name: Hydrolase
Title: Use of synthetic symmetrization in the crystallization and s determination of cela from thermotoga maritima
Structure: Endoglucanase. Chain: a, b. Engineered: yes. Mutation: yes
Source: Thermotoga maritima. Organism_taxid: 2336. Gene: tm1524, tm_1524. Expressed in: escherichia coli. Expression_system_taxid: 469008.
2.41Å     R-factor:   0.178     R-free:   0.216
Authors: G.J.Forse,N.Ram,T.O.Yeates
Key ref: G.J.Forse et al. (2011). Synthetic symmetrization in the crystallization and structure determination of CelA from Thermotoga maritima. Protein Sci, 20, 168-178. PubMed id: 21082721
30-Jul-10     Release date:   01-Dec-10    
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Protein chains
Pfam   ArchSchema ?
Q9S5X8  (Q9S5X8_THEMA) -  Endoglucanase
258 a.a.
264 a.a.*
Key:    PfamA domain  Secondary structure  CATH domain
* PDB and UniProt seqs differ at 1 residue position (black cross)

 Gene Ontology (GO) functional annotation 
  GO annot!
  Biological process     polysaccharide catabolic process   1 term 
  Biochemical function     hydrolase activity, hydrolyzing O-glycosyl compounds     2 terms  


Protein Sci 20:168-178 (2011)
PubMed id: 21082721  
Synthetic symmetrization in the crystallization and structure determination of CelA from Thermotoga maritima.
G.J.Forse, N.Ram, D.R.Banatao, D.Cascio, M.R.Sawaya, H.E.Klock, S.A.Lesley, T.O.Yeates.
Protein crystallization continues to be a major bottleneck in X-ray crystallography. Previous studies suggest that symmetric proteins, such as homodimers, might crystallize more readily than monomeric proteins or asymmetric complexes. Proteins that are naturally monomeric can be made homodimeric artificially. Our approach is to create homodimeric proteins by introducing single cysteines into the protein of interest, which are then oxidized to form a disulfide bond between the two monomers. By introducing the single cysteine at different sequence positions, one can produce a variety of synthetically dimerized versions of a protein, with each construct expected to exhibit its own crystallization behavior. In earlier work, we demonstrated the potential utility of the approach using T4 lysozyme as a model system. Here we report the successful application of the method to Thermotoga maritima CelA, a thermophilic endoglucanase enzyme with low sequence identity to proteins with structures previously reported in the Protein Data Bank. This protein had resisted crystallization in its natural monomeric form, despite a broad survey of crystallization conditions. The synthetic dimerization of the CelA mutant D188C yielded well-diffracting crystals with molecules in a packing arrangement that would not have occurred with native, monomeric CelA. A 2.4 Å crystal structure was determined by single anomalous dispersion using a seleno-methionine derivatized protein. The results support the notion that synthetic symmetrization can be a useful approach for enlarging the search space for crystallizing monomeric proteins or asymmetric complexes.