Binding of Ala-scanning analogs of omega-conotoxin MVIIC to N- and P/Q-type calcium channels.
omega-Conotoxin MVIIC binds to P/Q-type calcium channels with high affinity and N-type channels with low affinity. To reveal the residues essential for subtype selectivity, we synthesized Ala-scanning analogs of MVIIC. Binding assays using rat cerebellar P(2) membranes suggested that Thr(11), Tyr(13) and Lys(2) are essential for binding to both N- and P/Q-type channels, whereas Lys(4) and Arg(22) are important for binding to P/Q-type channels. These results suggest that MVIIC interacts with P/Q-type channels via a large surface, in good agreement with previous observations using chimeric analogs.
Sato
K
K
Mitsubishi Kasei Institute of Life Sciences, 11 Minamiooya, Machida, Tokyo, Japan. kazuki@libra.ls.m-kagaku.co.jp
Raymond
C
C
Martin-Moutot
N
N
Sasaki
T
T
Ohtake
A
A
Minami
K
K
Van Renterghem
C
C
Kim
J I
JI
Takahashi
M
M
Seagar
M J
MJ
D000409:Alanine / Q000737:chemistry*; D000595:Amino Acid Sequence; D000818:Animals; D002121:Calcium Channel Blockers / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism*; D020864:Calcium Channels, N-Type / Q000378:metabolism*; D020865:Calcium Channels, P-Type / Q000378:metabolism*; D020907:Calcium Channels, Q-Type / Q000378:metabolism*; D002531:Cerebellum / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D002942:Circular Dichroism; D004220:Disulfides / Q000737:chemistry; D066298:In Vitro Techniques; D007425:Intracellular Membranes / Q000502:physiology; D015640:Ion Channel Gating; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011485:Protein Binding; D051381:Rats; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013329:Structure-Activity Relationship; D020960:omega-Conotoxins / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism*
D002121:Calcium Channel Blockers; D020864:Calcium Channels, N-Type; D020865:Calcium Channels, P-Type; D020907:Calcium Channels, Q-Type; D004220:Disulfides; D020960:omega-Conotoxins; C075851:omega-conotoxin-MVIIC; D000409:Alanine