title: Glucose autoxidation induces functional damage to proteins via modification of critical arginine residues.
abstract: Nonenzymatic modification of proteins in hyperglycemia is a major mechanism causing diabetic complications. These modifications can have pathogenic consequences when they target active site residues, thus affecting protein function. In the present study, we examined the role of glucose autoxidation in functional protein damage using lysozyme and RGD-α3NC1 domain of collagen IV as model proteins in vitro. We demonstrated that glucose autoxidation induced inhibition of lysozyme activity as well as NC1 domain binding to α(V)β(3) integrin receptor via modification of critical arginine residues by reactive carbonyl species (RCS) glyoxal (GO) and methylglyoxal while nonoxidative glucose adduction to the protein did not affect protein function. The role of RCS in protein damage was confirmed using pyridoxamine which blocked glucose autoxidation and RCS production, thus protecting protein function, even in the presence of high concentrations of glucose. Glucose autoxidation may cause protein damage in vivo since increased levels of GO-derived modifications of arginine residues were detected within the assembly interface of collagen IV NC1 domains isolated from renal ECM of diabetic rats. Since arginine residues are frequently present within protein active sites, glucose autoxidation may be a common mechanism contributing to ECM protein functional damage in hyperglycemia and oxidative environment. Our data also point out the pitfalls in functional studies, particularly in cell culture experiments, that involve glucose treatment but do not take into account toxic effects of RCS derived from glucose autoxidation.
authors.affiliation: Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA.
authors.forename: Sergei
authors.initials: S
authors.lastname: Chetyrkin
authors.forename: Missy
authors.initials: M
authors.lastname: Mathis
authors.forename: Vadim
authors.initials: V
authors.lastname: Pedchenko
authors.forename: Otto A
authors.initials: OA
authors.lastname: Sanchez
authors.forename: W Hayes
authors.initials: WH
authors.lastname: McDonald
authors.forename: David L
authors.initials: DL
authors.lastname: Hachey
authors.forename: Hartman
authors.initials: H
authors.lastname: Madu
authors.forename: Donald
authors.initials: D
authors.lastname: Stec
authors.forename: Billy
authors.initials: B
authors.lastname: Hudson
authors.forename: Paul
authors.initials: P
authors.lastname: Voziyan
mesh_terms: D020816:Amino Acid Motifs; D000818:Animals; D001120:Arginine / Q000378:metabolism*; D024141:Collagen Type IV / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism; D003921:Diabetes Mellitus, Experimental / Q000201:enzymology / Q000378:metabolism; D005947:Glucose / Q000502:physiology*; D006037:Glyoxal / Q000009:adverse effects; D006943:Hyperglycemia / Q000201:enzymology / Q000378:metabolism; D008297:Male; D008837:Micrococcus / Q000201:enzymology; D009113:Muramidase / Q000037:antagonists & inhibitors / Q000378:metabolism; D050050:Protein Carbonylation; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism / Q000502:physiology*; D011765:Pyruvaldehyde / Q000009:adverse effects; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D024141:Collagen Type IV; D011506:Proteins; D006037:Glyoxal; D011765:Pyruvaldehyde; D001120:Arginine; D009113:Muramidase; D005947:Glucose