PDBsum entry 2kac

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protein links
Immune system PDB id
Jmol PyMol
Protein chain
64 a.a. *
* Residue conservation analysis
PDB id:
Name: Immune system
Title: Nmr solution structure of kx6e protl mutant
Structure: Protein l. Chain: a. Fragment: residues in database 111-173. Engineered: yes. Mutation: yes
Source: Peptostreptococcus magnus. Organism_taxid: 1260. Expressed in: escherichia coli. Expression_system_taxid: 562.
NMR struc: 20 models
Authors: B.Lopez-Mendez,X.Tadeo,M.Pons,O.Millet
Key ref: X.Tadeo et al. (2009). Structural basis for the aminoacid composition of proteins from halophilic archea. PLoS Biol, 7, e1000257. PubMed id: 20016684
04-Nov-08     Release date:   20-Oct-09    
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Protein chain
Pfam   ArchSchema ?
Q51912  (Q51912_PEPMA) -  Putative uncharacterized protein
719 a.a.
64 a.a.*
Key:    PfamA domain  PfamB domain  Secondary structure  CATH domain
* PDB and UniProt seqs differ at 8 residue positions (black crosses)


PLoS Biol 7:e1000257 (2009)
PubMed id: 20016684  
Structural basis for the aminoacid composition of proteins from halophilic archea.
X.Tadeo, B.López-Méndez, T.Trigueros, A.Laín, D.Castaño, O.Millet.
Proteins from halophilic organisms, which live in extreme saline conditions, have evolved to remain folded at very high ionic strengths. The surfaces of halophilic proteins show a biased amino acid composition with a high prevalence of aspartic and glutamic acids, a low frequency of lysine, and a high occurrence of amino acids with a low hydrophobic character. Using extensive mutational studies on the protein surfaces, we show that it is possible to decrease the salt dependence of a typical halophilic protein to the level of a mesophilic form and engineer a protein from a mesophilic organism into an obligate halophilic form. NMR studies demonstrate complete preservation of the three-dimensional structure of extreme mutants and confirm that salt dependency is conferred exclusively by surface residues. In spite of the statistically established fact that most halophilic proteins are strongly acidic, analysis of a very large number of mutants showed that the effect of salt on protein stability is largely independent of the total protein charge. Conversely, we quantitatively demonstrate that halophilicity is directly related to a decrease in the accessible surface area.

Literature references that cite this PDB file's key reference

  PubMed id Reference
21539921 F.Liu, J.Xiong, S.Kumar, C.Yang, S.Ge, S.Li, N.Xia, and K.Swaminathan (2011).
Structural and biophysical characterization of Mycobacterium tuberculosis dodecin Rv1498A.
  J Struct Biol, 175, 31-38.
PDB code: 3oqt
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