The conformation formed by the domain after alanine-155 induces inversion of aspartic acid-151 in alpha A-crystallin from aged human lenses.
A new cleavage site, which is a post-translational modification, was found between residues His-154 and Ala-155 in alpha A-crystallin from the aged human lens. After trypsin digestion of alpha A-crystallin two peptides that include Asp-151 were obtained and have remarkable differences. That is, the stereo-configuration of the Asp-151 in the normal length peptide was predominately inverted to the D-isomer of beta-aspartyl form (D/L of 5.7). However, the stereoconfiguration of the Asp-151 in the cleavage peptide, that lacks the sequence following Ala-155 to the C-terminus, remained predominately in the L-isomer form as indicated by a D/L value of 0.3. The results suggest that the secondary structure in the region of Ala-155 to the C-terminus may constitute a field that causes the inversion of the Asp-151 to the D-isomer form. Since this kind of cleavage was not found in alpha A-crystallin from young lens, the cleavage between His-154 and Ala-155 is probably the result of aging.
Fujii
N
N
Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Corporation (JST), Ibaraki.
Momose
Y
Y
Yamasaki
M
M
Yamagaki
T
T
Nakanishi
H
H
Uemura
T
T
Takita
M
M
Ishii
N
N
D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D000409:Alanine / Q000378:metabolism*; D000595:Amino Acid Sequence; D001224:Aspartic Acid / Q000378:metabolism*; D003459:Crystallins / Q000302:isolation & purification / Q000378:metabolism* / Q000502:physiology; D006801:Humans; D007223:Infant; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D017421:Sequence Analysis; D014357:Trypsin
D003459:Crystallins; D010446:Peptide Fragments; D001224:Aspartic Acid; D014357:Trypsin; D000409:Alanine