Photolabeled tryptic degradation products of benzodiazepine‐binding proteins are glycopeptides Implications for localization of cleavage sites

FEBS Letters

Schmitz, Elke¹  Möhler, Hanns²  Hebebrand, Johannes¹  Reichelt, Ralf¹ 

[1] Institut für Humangenetik der Universität Bonn, Wilhelmstr. 31, D-5300 Bonn 1, FRG;Pharmaceutical Research Department, F. Hoffmann-La Roche & Co., Ltd, CH-4002 Basle, Switzerland

关键词: Aminobutyric acid receptor;    γ-;    Benzodiazepine receptor;    Deglycosylation;    Tryptic degradation;    Photoaffinity labeling;    Transmembrane topology;    Immunoblotting;   

DOI  :  10.1016/0014-5793(89)80578-2

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Crude synaptic membranes of avian and mammalian brain tissue were photolabeled with the benzodiazepine-receptor ligand [³H]flunitrazepam and subsequently treated extensively with trypsin followed by incubation with endoglycosidase F. SDS-polyacrylamide gel electrophoresis and fluorography revealed that the final tryptic degradation product of 25 kDa in both pigeon and calf brain is deglycosylated in two steps. These results were confirmed by immunoblots of similarly pretreated membranes of pig brain using the α-subunit-specific monoclonal antibody bd-24. Benzodiazepine-receptor binding and its enhancement by GABA are largely retained after trypsinization. Based on the proposed transmembrane topology for the α-subunits of the GABA/benzodiazepine receptor, we suggest that the large N-terminal domain of benzodiazepine-binding proteins is protected against tryptic cleavage.

【 授权许可】

Unknown