Alpha-crystallin: an ATP-independent complete molecular chaperone toward sorbitol dehydrogenase

• Published in: Cellular and molecular life sciences : CMLS Vol. 62; no. 5; pp. 599 - 605
• Main Authors: Marini, I, Moschini, R, Corso, A. Del, Mura, U
• Format: Journal Article
• Language: English
• Published: Switzerland Birkhäuser-Verlag 01-03-2005; Springer Nature B.V
• Subjects: adenosine triphosphate; Adenosine Triphosphate - chemistry; Adenosine Triphosphate - physiology; alpha-Crystallins - chemistry; alpha-Crystallins - metabolism; Animals; ATP; Cattle; Chemical activity; Crystallin; Dehydrogenase; Denaturation; energy; Enzymatic activity; Enzyme Activation - physiology; Enzyme activity; Enzymes; Guanidine - pharmacology; Heat shock proteins; hydrolysis; Inactivation; L-Iditol 2-Dehydrogenase - chemistry; L-Iditol 2-Dehydrogenase - drug effects; L-Iditol 2-Dehydrogenase - metabolism; L-iditol dehydrogenase; Lenses; Molecular biology; molecular chaperones; NAD (coenzyme); NAD - chemistry; NAD - physiology; Protein Denaturation; Protein Folding; pyridines; Recovery; Renaturation; Sorbitol; Vertebrates
• ISSN: 1420-682X; 1420-9071
• DOI: 10.1007/s00018-005-4474-z

α-Crystallin, the major component of the vertebrate lens, is known to interact with proteins undergoing denaturation and to protect them from aggregation phenomena. Bovine lens sorbitol dehydrogenase (SDH) was previously shown to be completely protected by α-crystallin from thermally induced aggregation and inactivation. Here we report that α-crystallin, in the presence of the SDH pyridine cofactor NAD(H), can exert a remarkable chaperone action by favoring the recovery of the enzyme activity from chemically denaturated SDH up to 77%. Indeed, even in the absence of the cofactor, α-crystallin present at a ratio with SDH of 20:1 (w:w) allows a recovery of 35% of the enzyme activity. The effect of ATP in enhancing α-crystallin-promoted SDH renaturation appears to be both nonspecific and to not involve hydrolysis phenomena, thus confirming that the chaperone action of α-crystallin is not dependent on ATP as energy donor.