Key points are not available for this paper at this time.
γ-Secretase is a multimeric membrane protein complex composed of presenilin (PS), nicastrin, Aph-1 and, Pen-2 that is responsible for the intramembrane proteolysis of various type I transmembrane proteins, including amyloid β-precursor protein and Notch. The direct labeling of PS polypeptides by transition-state analogue γ-secretase inhibitors suggested that PS represents the catalytic center of γ-secretase. Here we show that one of the major γ-secretase inhibitors of dipeptidic type, N-N-(3,5-difluorophenacetyl)-l-alanyl-S-phenylglycine t-butyl ester (DAPT), targets the C-terminal fragment of PS, especially the transmembrane domain 7 or more C-terminal region, by designing and synthesizing DAP-BpB (N-N-(3,5-difluorophenacetyl)-l-alanyl-(S)-phenylglycine-4-(4-(8-biotinamido)octylamino)benzoyl)benzyl)methylamide), a photoactivable DAPT derivative. We also found that DAP-BpB selectively binds to the high molecular weight γ-secretase complex in an activity-dependent manner. Photolabeling of PS by DAP-BpB is completely blocked by DAPT or its structural relatives (e.g. Compound E) as well as by arylsulfonamides. In contrast, transition-state analogue inhibitor L-685,458 or α-helical peptidic inhibitor attenuated the photolabeling of the DAPT as a domain the PS C-terminal fragment that is the catalytic or the γ-Secretase is a multimeric membrane protein complex composed of presenilin (PS), nicastrin, Aph-1 and, Pen-2 that is responsible for the intramembrane proteolysis of various type I transmembrane proteins, including amyloid β-precursor protein and Notch. The direct labeling of PS polypeptides by transition-state analogue γ-secretase inhibitors suggested that PS represents the catalytic center of γ-secretase. Here we show that one of the major γ-secretase inhibitors of dipeptidic type, N-N-(3,5-difluorophenacetyl)-l-alanyl-S-phenylglycine t-butyl ester (DAPT), targets the C-terminal fragment of PS, especially the transmembrane domain 7 or more C-terminal region, by designing and synthesizing DAP-BpB (N-N-(3,5-difluorophenacetyl)-l-alanyl-(S)-phenylglycine-4-(4-(8-biotinamido)octylamino)benzoyl)benzyl)methylamide), a photoactivable DAPT derivative. We also found that DAP-BpB selectively binds to the high molecular weight γ-secretase complex in an activity-dependent manner. Photolabeling of PS by DAP-BpB is completely blocked by DAPT or its structural relatives (e.g. Compound E) as well as by arylsulfonamides. In contrast, transition-state analogue inhibitor L-685,458 or α-helical peptidic inhibitor attenuated the photolabeling of the DAPT as a domain the PS C-terminal fragment that is the catalytic or the of that γ-secretase is a high molecular weight high molecular C-terminal t-butyl PS, transmembrane high molecular C-terminal t-butyl PS, transmembrane membrane protein including presenilin (PS), nicastrin, and Pen-2 PS is fragment and C-terminal fragment the and to the of fragment a that for γ-secretase inhibitors to PS that PS is the catalytic of γ-secretase. transition-state analogue to the catalytic γ-secretase its inhibitors a an α-helical inhibitor binds to PS in a to that of transition-state analogue inhibitors that γ-secretase a that is the catalytic to the of binds the of and γ-secretase inhibitors in to the transition-state molecular and of we one of analogue γ-secretase t-butyl ester DAPT of to the in the and the the the that γ-secretase inhibitors the of DAPT to the of We the 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Morohashi et al. (Wed,) studied this question.