The C-terminal region of alpha-crystallin: involvement in protection against heat-induced denaturation.
Recent studies have demonstrated that the alpha-crystallins can protect other proteins against heat-induced denaturation and aggregation. To determine the possible involvement of the C-terminal region in this activity, the alpha-crystallins were subjected to limited tryptic digestion, and the amount of cleavage from the N-terminal and C-terminal regions of the alpha-A and alpha-B crystallin chains was assessed using antisera specific for these regions. Limited tryptic digestion resulted in cleavage only from the C-terminal region of alpha-A crystallin. This trypsin-treated alpha-A crystallin preparation showed a decreased ability to protect proteins from heat-induced aggregation using an in vitro assay. Together, these results demonstrate that the C-terminal region of alpha-A crystallin is important for its ability to protect against heat-induced aggregation, which is consistent with the hypothesis that post-translational changes that are known to occur at the C-terminal region may have significant effects on the ability of alpha-A crystallin to protect against protein denaturation in vivo.
Division of Biology, Kansas State University, Manhattan 66506.
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Takemoto
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Emmons
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Horwitz
D000426:Alcohol Dehydrogenase / Q000737:chemistry; D000595:Amino Acid Sequence; D000818:Animals; D000831:Animals, Newborn; D002417:Cattle; D003459:Crystallins / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology; D006358:Hot Temperature; D015151:Immunoblotting; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D011489:Protein Denaturation / Q000187:drug effects*; D011499:Protein Processing, Post-Translational; D013329:Structure-Activity Relationship; D014357:Trypsin / Q000378:metabolism
D003459:Crystallins; D010446:Peptide Fragments; D000426:Alcohol Dehydrogenase; D014357:Trypsin