title: Fungicide methyl thiophanate binding at sub-domain IIA of human serum albumin triggers conformational change and protein damage.
abstract: Fluorescence quenching data on interaction of a fungicide methyl thiophanate (MT) with human serum albumin (HSA) elucidated a primary binding site at sub-domain IIA. Stern-Volmer algorithm and double log plot revealed the binding affinity (K(a)) and capacity (n) of HSA as 1.65 x 10(4)M(-1) and 1.0 (r(2)=0.99), respectively. Cyclic voltammetric and circular dichroism (CD) studies reaffirmed MT-HSA binding and demonstrated reduction in alpha-helical content of HSA. Substantial release of the carbonyl and acid-soluble amino groups from MT treated HSA suggested protein damage. The plausible mechanism of methyl ((+)CH(3)) group transfer from MT to side chain NH group of tryptophan and HSA degradation elucidates the toxicological and clinical implications of this fungicide.
authors.affiliation: Al-Jeraisy Chair for DNA Research, College of Science, P.O. Box 2455, King Saud University, Riyadh 11451, Saudi Arabia.
authors.forename: Quaiser
authors.initials: Q
authors.lastname: Saquib
authors.forename: Abdulaziz A
authors.initials: AA
authors.lastname: Al-Khedhairy
authors.forename: Saud A
authors.initials: SA
authors.lastname: Alarifi
authors.forename: Sourabh
authors.initials: S
authors.lastname: Dwivedi
authors.forename: Jamal
authors.initials: J
authors.lastname: Mustafa
authors.forename: Javed
authors.initials: J
authors.lastname: Musarrat
mesh_terms: D000465:Algorithms; D002942:Circular Dichroism; D005659:Fungicides, Industrial / Q000737:chemistry*; D006801:Humans; D017434:Protein Structure, Tertiary; D012709:Serum Albumin / Q000737:chemistry*; D013875:Thiophanate / Q000737:chemistry*; D014364:Tryptophan / Q000737:chemistry
chemical_list: D005659:Fungicides, Industrial; D012709:Serum Albumin; D013875:Thiophanate; D014364:Tryptophan