Effect of SNPs on creatine kinase structure and function: identifying potential molecular mechanisms for possible creatine kinase deficiency diseases.
Single-nucleotide polymorphisms (SNPs) are common genetic material changes that often occur naturally. SNPs can cause amino acid replacements that may lead to severe diseases, such as the well-known sickle-cell anemia. We constructed eight SNP mutants of human brain-type creatine kinase (CKB) based on bioinformatics predictions. The biochemical and biophysical characteristics of these SNP mutants were determined and compared to those of the wild-type creatine kinase to explore the potential molecular mechanisms of possible creatine kinase SNP-induced diseases. While the reactivation of six SNP mutants after heat shock dropped more than 45%, only three of them showed notable increases in ANS fluorescence intensity and decreases in catalytic efficiency. Among them, H26Y and P36T bind substrates as well as the wild-type form does, but the melting temperatures (T(m)) dropped below body temperature, while the T59I mutant exhibited decreased catalytic activity that was most likely due to the much reduced binding affinity of this mutant for substrates. These findings indicate that SNPs such as H26Y, P36T and T59I have the potential to induce genetic diseases by different mechanisms.
Protein Science Laboratory of the Ministry of Education, School of Life Sciences, Tsinghua University, Beijing, P.R. China.
Chang
C
Li
Qian
Q
Zhang
Wei-Jiang
WJ
Hu
Hang
H
Mu
Zong
Z
Lin
Long
L
Ma
Yong-Doo
YD
Park
Hai-Meng
HM
Zhou
D001703:Biophysics / Q000379:methods; D001921:Brain / Q000201:enzymology; D002384:Catalysis; D002850:Chromatography, Gel; D019295:Computational Biology / Q000379:methods; D003402:Creatine Kinase / Q000172:deficiency* / Q000235:genetics*; D019281:Dimerization; D006358:Hot Temperature; D006801:Humans; D015233:Models, Statistical; D009154:Mutation; D020641:Polymorphism, Single Nucleotide; D013050:Spectrometry, Fluorescence / Q000379:methods; D013696:Temperature
D003402:Creatine Kinase