The effect of Trp83 mutant on the properties of CopC.
CopC, a protein involved in copper resistance, is essentially constituted by two sheets forming a Greek key beta barrel motif. The aromatic ring of Trp83, sandwiched between the two beta sheets, has numerous contacts with residues in strands beta and stabilizes the protein fold. In the paper Trp83 was mutated to Leu to study the effect of this mutation on CopC by means of fluorescence spectra and UV spectra. The experiments indicate that the mutation bind Cu(2+) with a decreased formation constant of 3.95 x 10(11) M(-1) in 20 mM PB buffer at pH 7.0; mutagenesis make hydrophobic region to be exposed to an extent. Compared with the wild, thermal stability of the mutant was shown to decrease by stronger fluorescence of TNS at 80 degrees C. The important role of aromatic residue in structure is exhibited.
Li
Hui-Qin
HQ
Institute of Molecular Science, Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Shanxi University, Taiyuan 030006, China.
Zheng
Xiao-Yan
XY
Pang
Er-Guo
EG
Zhao
Ya-Qin
YQ
Yang
Bin-Sheng
BS
D001426:Bacterial Proteins / Q000378:metabolism*; D003300:Copper / Q000378:metabolism; D050505:Mutant Proteins / Q000378:metabolism; D009154:Mutation / Q000235:genetics*; D011487:Protein Conformation; D044224:Pseudomonas syringae / Q000378:metabolism*; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D013329:Structure-Activity Relationship; D013816:Thermodynamics; D014364:Tryptophan / Q000235:genetics*
D001426:Bacterial Proteins; C071265:CopC protein, Bacteria; D050505:Mutant Proteins; D003300:Copper; D014364:Tryptophan