Copper II complex of a tridentate ligand: an artificial metalloprotease for bovine serum albumin.
A copper(II) complex of 2, 6-bis(benzimidazo-2-yl) pyridine was synthesized and its binding properties with bovine serum albumin (BSA) has been evaluated. The binding plot obtained from the absorption titration data gives a binding constant of 2.4 (+/-0.3) x10(3) M(-1). It was found that the charge transfer band of the metal complex was perturbed in the presence of BSA. The gel electrophoresis pattern of BSA incubated with copper(II) complex shows the metalloproteolytic activity of the metal complex. In the presence of oxygen, protein undergoes site-specific cleavage by binding to the histidine residues of domain III, with the resultant formation of four fragments of molecular weight 49, 45, 22 and 17 kDa. This indicates the presence of two specific binding sites in the protein molecule. In the absence of molecular oxygen, the metal complex was found unable to cleave the protein. The circular dichroism (CD) spectrum of the isolated fragments shows nearly 38% and 32% of alpha helical content in 49 and 45 kDa fragments, respectively, which shows that the cleavage leads to no changes in the secondary structure of the protein fragments.
Shrivastava
H Yamini
HY
Chemical Laboratory, Central Leather Research Institute, Adyar, Chennai 600 020, India.
Kanthimathi
Mookandi
M
Nair
Balachandran Unni
BU
D001562:Benzimidazoles / Q000138:chemical synthesis / Q000737:chemistry; D001665:Binding Sites; D002942:Circular Dichroism; D003300:Copper / Q000737:chemistry*; D004591:Electrophoresis, Polyacrylamide Gel; D008024:Ligands; D008666:Metalloendopeptidases / Q000138:chemical synthesis / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry; D012710:Serum Albumin, Bovine / Q000737:chemistry*
D001562:Benzimidazoles; D008024:Ligands; D012710:Serum Albumin, Bovine; D003300:Copper; D008666:Metalloendopeptidases; D010100:Oxygen