Study On 3-D Structure Model Of BK Channel

Large conductance potassium channel (BK channel) is a special channel modulated by the membrane voltage and intracellular calcium channels. It plays a very important role in modulating many important physiological processes, such as frequency regulation of ear hair cells and hormone secretion, neurotransmitter release, heart rate and vascular resistance. Therefore, the structure of BK channel and its regulation mechanism are of great significance to the research of neuroscience and cardiovascular disease.By using BLAST, the homology of mslo1 was searched in the protein structure database (PDB database). According to the scores of the results, the structure of transmembrane domains (S1-S6) were constructed using the 3-D structure of the mammalian Kv1.2 channel (PDB ID, 2R9R) as a template by MODELLER. The structure of N-terminal was constructed using ab initio method by ROSETTA. The structure of RCK was directly from the 3-D structure of hslo1 (PDB ID, 3NAF). Finally, the whole structure of BK channels has been constructed by taking the MthK channel and the cryo-EM BK structure as reference .With the sequence alignment of BK channel and KCNQ1 channel, four residues in BK channel were found to share a common interface between the S1 segment of the voltage in one subunit and both the S5 segment and top of the pore helix from another subunit. This interface may play an important role in channel gating. Additionally, the S0-S1 linker's structure of dslo1 was constructed by ROSETTA. And it has been found that the S0-S1 linker of mslo1 has two moreα-helices than that of dslo1. The corresponding structure in dslo1 is a loop without stable conformation. This loop may interrupt the activation ofβ2 and BK channel.