The positively charged residues in the fragment 71-77 of complexin is required for its binding to SNARE complex

Abstract

Complexin is a cytoplasmic protein that plays an important role in the neurotransmitters release triggered by action potential. Previous studies suggested that complexin performs its functions through interaction with the SNARE complex. The crystal structure of complexin/SNARE complex revealed that complexin binds to SNARE core complex in an anti-parallel conformation with its residues 48-70. However, the functions of the flanking sequences are unclear. In this paper, we demonstrate that the fragment 71-77 of complexin is indispensable for its binding to the SNARE complex. Moreover, this interaction can be impaired by abolishing the positive charges in the fragment 71-77, which suggests that the positive charges in the fragment 71-77 are important for the interaction between complexin II and the SNARE complex. © 2007 IUBMB.