Binding of six chimeric analogs of omega-conotoxin MVIIA and MVIIC to N- and P/Q-type calcium channels.
Replacement of the N-terminal half of omega-conotoxin MVIIC, a peptide blocker of P/Q-type calcium channels, with that of omega-conotoxin MVIIA significantly increased the affinity for N-type calcium channels. To identify the residues essential for subtype selectivity, we examined single reverse mutations from MVIIA-type to MVIIC-type in this chimeric analog. A reverse mutation from Lys(7) to Pro(7) decreased the affinity for both P/Q- and N-type channels, whereas that from Leu(11) to Thr(11) increased the affinity for P/Q-type channels and decreased the affinity for N-type channels. The roles of these two residues were confirmed by synthesizing two MVIIC analogs in which Pro(7) and Thr(11) were replaced with Lys(7) and Leu(11), respectively.
Sato
K
K
Mitsubishi Kasei Institute of Life Sciences, 11 Minamiooya, Machida, Tokyo, 194-8511, 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
Takahashi
M
M
Seagar
M J
MJ
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites / Q000235:genetics; D002121:Calcium Channel Blockers / Q000737:chemistry / Q000378:metabolism; D015220:Calcium Channels / Q000145:classification / 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; D002942:Circular Dichroism; D066298:In Vitro Techniques; D008969:Molecular Sequence Data; D009154:Mutation; D011485:Protein Binding; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D020960:omega-Conotoxins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*
D002121:Calcium Channel Blockers; D015220:Calcium Channels; D020864:Calcium Channels, N-Type; D020865:Calcium Channels, P-Type; D020907:Calcium Channels, Q-Type; D011993:Recombinant Fusion Proteins; D020960:omega-Conotoxins; C075851:omega-conotoxin-MVIIC; C078452:ziconotide