TY - JOUR
T1 - A pathway for conformational diversity in proteins mediated by intramolecular chaperones
AU - Shinde, Ujwal
AU - Fu, Xuan
AU - Inouye, Masayori
PY - 1999/5/28
Y1 - 1999/5/28
N2 - Conformational diversity within unique amino acid sequences is observed in diseases like scrapie and Alzheimer's disease. The molecular basis of such diversity is unknown. Similar phenomena occur in subtilisin, a serine protease homologous with eukaryotic pro-hormone convertases. The subtilisin propeptide functions as an intramolecular chaperone (IMC) that imparts steric information during folding but is not required for enzymatic activity. Point mutations within IMCs alter folding, resulting in structural conformers that specifically interact with their cognate IMCs in a process termed 'protein memory.' Here, we show a mechanism that mediates conformational diversity in subtilisin. During maturation, while the IMC is autocleaved and subsequently degraded by the active site of subtilisin, enzymatic properties of this site differ significantly before and after cleavage. Although subtilisin folded by Ile-48 → Thr IMC (IMC(I-48T)) acquires an 'altered' enzymatically active conformation (Sub(I-48T)) significantly different from wild-type subtilisin (Sub(WT)), both precursors undergo autocleavage at similar rates. IMC cleavage initiates conformational changes during which the IMC continues its chaperoning function subsequent to its cleavage from subtilisin. Structural imprinting resulting in conformational diversity originates during this reorganization stage and is a late folding event catalyzed by autocleavage of the IMC.
AB - Conformational diversity within unique amino acid sequences is observed in diseases like scrapie and Alzheimer's disease. The molecular basis of such diversity is unknown. Similar phenomena occur in subtilisin, a serine protease homologous with eukaryotic pro-hormone convertases. The subtilisin propeptide functions as an intramolecular chaperone (IMC) that imparts steric information during folding but is not required for enzymatic activity. Point mutations within IMCs alter folding, resulting in structural conformers that specifically interact with their cognate IMCs in a process termed 'protein memory.' Here, we show a mechanism that mediates conformational diversity in subtilisin. During maturation, while the IMC is autocleaved and subsequently degraded by the active site of subtilisin, enzymatic properties of this site differ significantly before and after cleavage. Although subtilisin folded by Ile-48 → Thr IMC (IMC(I-48T)) acquires an 'altered' enzymatically active conformation (Sub(I-48T)) significantly different from wild-type subtilisin (Sub(WT)), both precursors undergo autocleavage at similar rates. IMC cleavage initiates conformational changes during which the IMC continues its chaperoning function subsequent to its cleavage from subtilisin. Structural imprinting resulting in conformational diversity originates during this reorganization stage and is a late folding event catalyzed by autocleavage of the IMC.
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U2 - 10.1074/jbc.274.22.15615
DO - 10.1074/jbc.274.22.15615
M3 - Article
C2 - 10336458
AN - SCOPUS:0033059499
SN - 0021-9258
VL - 274
SP - 15615
EP - 15621
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 22
ER -