TY - JOUR
T1 - Molecular requirements for recognition of brain voltage-gated sodium channels by scorpion α-toxins
AU - Kahn, Roy
AU - Karbat, Izhar
AU - Ilan, Nitza
AU - Cohen, Lior
AU - Sokolov, Stanislav
AU - Catterall, William A.
AU - Gordon, Dalia
AU - Gurevitz, Michael
PY - 2009/7/31
Y1 - 2009/7/31
N2 - The scorpion α-toxin Lqh2 (firqm Leiurus quinquestriatus hebraeus) is active at various mammalian voltage-gated sodium channels (Navs) and is inactive it insect Navs. To resolve the molecular basis of this preference we used the following strategy: 1) Lqh2 was expressed in recombinant form and key residues important for activity at the rat brain channel rNav1.2a were identified by mutagenesis. These residues form a bipartite functional surface made of a conserved "core domain" (residues of the loops connecting the secondary structure elements of the molecule core), and a variable "NC domain" (five-residue turn and the C-tail) as was reported for other scorpion α-toxins. 2) The functional role of the two domains was validated by their stepwise construction on the similar scaffold of the anti-insect toxin LqhαIT. Analysis of the activity of the intermediate constructs highlighted the critical role of Phe15 of the core domain in toxin potency at rNav1.2a, and has suggested that the shape of the NC-domain is important for toxin efficacy. 3) Based on these findings and by comparison with other scorpion α-toxins we were able to eliminate the activity of Lqh2 at rNav1.4 (skeletal muscle), hNav1.5 (cardiac), and rNav1.6 channels, with no hindrance of its activity at Nav.1.1-1.3. These results suggest that by employing a similar approach the design of further target-selective sodium channel modifiers is imminent.
AB - The scorpion α-toxin Lqh2 (firqm Leiurus quinquestriatus hebraeus) is active at various mammalian voltage-gated sodium channels (Navs) and is inactive it insect Navs. To resolve the molecular basis of this preference we used the following strategy: 1) Lqh2 was expressed in recombinant form and key residues important for activity at the rat brain channel rNav1.2a were identified by mutagenesis. These residues form a bipartite functional surface made of a conserved "core domain" (residues of the loops connecting the secondary structure elements of the molecule core), and a variable "NC domain" (five-residue turn and the C-tail) as was reported for other scorpion α-toxins. 2) The functional role of the two domains was validated by their stepwise construction on the similar scaffold of the anti-insect toxin LqhαIT. Analysis of the activity of the intermediate constructs highlighted the critical role of Phe15 of the core domain in toxin potency at rNav1.2a, and has suggested that the shape of the NC-domain is important for toxin efficacy. 3) Based on these findings and by comparison with other scorpion α-toxins we were able to eliminate the activity of Lqh2 at rNav1.4 (skeletal muscle), hNav1.5 (cardiac), and rNav1.6 channels, with no hindrance of its activity at Nav.1.1-1.3. These results suggest that by employing a similar approach the design of further target-selective sodium channel modifiers is imminent.
UR - http://www.scopus.com/inward/record.url?scp=68949137013&partnerID=8YFLogxK
U2 - 10.1074/jbc.M109.021303
DO - 10.1074/jbc.M109.021303
M3 - Article
C2 - 19509294
AN - SCOPUS:68949137013
SN - 0021-9258
VL - 284
SP - 20684
EP - 20691
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 31
ER -