title: Protective Effects of Acetylation on the Pathological Reactions of the Lens Crystallins with Homocysteine Thiolactone.
abstract: Various post-translational lens crystallins modifications result in structural and functional insults, contributing to the development of lens opacity and cataract disorders. Lens crystallins are potential targets of homocysteinylation, particularly under hyperhomocysteinemia which has been indicated in various eye diseases. Since both homocysteinylation and acetylation primarily occur on protein free amino groups, we applied different spectroscopic methods and gel mobility shift analysis to examine the possible preventive role of acetylation against homocysteinylation. Lens crystallins were extensively acetylated in the presence of acetic anhydride and then subjected to homocysteinylation in the presence of homocysteine thiolactone (HCTL). Extensive acetylation of the lens crystallins results in partial structural alteration and enhancement of their stability, as well as improvement of α-crystallin chaperone-like activity. In addition, acetylation partially prevents HCTL-induced structural alteration and aggregation of lens crystallins. Also, acetylation protects against HCTL-induced loss of α-crystallin chaperone activity. Additionally, subsequent acetylation and homocysteinylation cause significant proteolytic degradation of crystallins. Therefore, further experimentation is required in order to judge effectively the preventative role of acetylation on the structural and functional insults induced by homocysteinylation of lens crystallins.
authors.affiliation: Protein Chemistry Laboratory (PCL), Department of Biology, College of Sciences, Shiraz University, Shiraz, Iran.
authors.forename: Zeinab
authors.initials: Z
authors.lastname: Moafian
authors.affiliation: Protein Chemistry Laboratory (PCL), Department of Biology, College of Sciences, Shiraz University, Shiraz, Iran.
authors.forename: Kazem
authors.initials: K
authors.lastname: Khoshaman
authors.affiliation: Department of Pathology, School of Veterinary Medicine, Shiraz University, Shiraz, Iran.
authors.forename: Ahmad
authors.initials: A
authors.lastname: Oryan
authors.affiliation: Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences, Leninsky pr. 33, Moscow, 119071, Russia.
authors.forename: Boris I
authors.initials: BI
authors.lastname: Kurganov
authors.affiliation: Protein Chemistry Laboratory (PCL), Department of Biology, College of Sciences, Shiraz University, Shiraz, Iran.
authors.forename: Reza
authors.initials: R
authors.lastname: Yousefi
mesh_terms: D000107:Acetylation; D000818:Animals; D002417:Cattle; D002942:Circular Dichroism; D006710:Homocysteine / Q000031:analogs & derivatives* / Q000494:pharmacology; D006801:Humans; D007908:Lens, Crystalline / Q000187:drug effects*; D008855:Microscopy, Electron, Scanning; D011487:Protein Conformation / Q000187:drug effects; D011499:Protein Processing, Post-Translational; D055550:Protein Stability / Q000187:drug effects; D038201:alpha-Crystallins / Q000737:chemistry* / Q000235:genetics
chemical_list: D038201:alpha-Crystallins; D006710:Homocysteine; C007957:homocysteine thiolactone