1wwn: Difference between revisions

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'''NMR Solution Structure of BmK-betaIT, an Excitatory Scorpion Toxin from Buthus martensi Karsch'''<br />

==Overview==

BmK-betaIT (previously named as Bm32-VI in the literature), an excitatory, scorpion beta-toxin, is purified from the venom of the Chinese scorpion, Buthus martensii Karsch. It features a primary sequence typical of the, excitatory anti-insect toxins: two contiguous Cys residues (Cys37-Cys38), and a shifted location of the fourth disulfide bridges (Cys38-Cys64), and, demonstrates bioactivity characteristic of the excitatory beta-toxins., However, it is noteworthy that BmK-betaIT is not conserved with a, glutamate residue at the preceding position of the third Cys residue, and, is the first example having a non-glutamate residue at the relevant, position in the excitatory scorpion beta-toxin subfamily. The 3D structure, of BmK-betaIT is determined with 2D NMR spectroscopy and molecular, modeling. The solution structure of BmK-betaIT is closely similar to those, of BmK IT-AP and Bj-xtrIT, only distinct from the latter by lack of an, alpha(0)-helix. The surface functional patch comparison with those of BmK, IT-AP and Bj-xtrIT reveals their striking similarity in the spatial, arrangement. These results infer that the functional surface of, beta-toxins is composed of two binding regions and a functional site. The, main binding site is consisted of hydrophobic residues surrounding the, alpha(1)-helix and its preceding loop, which is common to all beta-type, scorpion toxins affecting Na(+) channels. The second binding site, which, determines the specificity of the toxin, locates at the C-terminus for, excitatory insect beta-toxin, while rests at the beta-sheet and its, linking loop for anti-mammal toxins. The functional site involved in the, voltage sensor-trapping model, which characterizes the function of all, beta-toxins, is the negatively charged residue Glu15.

BmK-betaIT (previously named as Bm32-VI in the literature), an excitatory scorpion beta-toxin, is purified from the venom of the Chinese scorpion Buthus martensii Karsch. It features a primary sequence typical of the excitatory anti-insect toxins: two contiguous Cys residues (Cys37-Cys38) and a shifted location of the fourth disulfide bridges (Cys38-Cys64), and demonstrates bioactivity characteristic of the excitatory beta-toxins. However, it is noteworthy that BmK-betaIT is not conserved with a glutamate residue at the preceding position of the third Cys residue, and is the first example having a non-glutamate residue at the relevant position in the excitatory scorpion beta-toxin subfamily. The 3D structure of BmK-betaIT is determined with 2D NMR spectroscopy and molecular modeling. The solution structure of BmK-betaIT is closely similar to those of BmK IT-AP and Bj-xtrIT, only distinct from the latter by lack of an alpha(0)-helix. The surface functional patch comparison with those of BmK IT-AP and Bj-xtrIT reveals their striking similarity in the spatial arrangement. These results infer that the functional surface of beta-toxins is composed of two binding regions and a functional site. The main binding site is consisted of hydrophobic residues surrounding the alpha(1)-helix and its preceding loop, which is common to all beta-type scorpion toxins affecting Na(+) channels. The second binding site, which determines the specificity of the toxin, locates at the C-terminus for excitatory insect beta-toxin, while rests at the beta-sheet and its linking loop for anti-mammal toxins. The functional site involved in the voltage sensor-trapping model, which characterizes the function of all beta-toxins, is the negatively charged residue Glu15.

==About this Structure==

1WWN is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Mesobuthus_martensii Mesobuthus martensii]. Full crystallographic information is available from [http://~~ispc~~.weizmann.ac.il/oca-bin/ocashort?id=1WWN OCA].

1WWN is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Mesobuthus_martensii Mesobuthus martensii]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1WWN OCA].

==Reference==

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[[Category: an excitatory scorpion toxin]]

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-[[Image:1wwn.gif|left|200px]]<br /><applet load="1wwn" size="450" color="white" frame="true" align="right" spinBox="true"
+[[Image:1wwn.gif|left|200px]]<br /><applet load="1wwn" size="350" color="white" frame="true" align="right" spinBox="true"
 caption="1wwn" />
 '''NMR Solution Structure of BmK-betaIT, an Excitatory Scorpion Toxin from Buthus martensi Karsch'''<br />
 ==Overview==
-BmK-betaIT (previously named as Bm32-VI in the literature), an excitatory, scorpion beta-toxin, is purified from the venom of the Chinese scorpion, Buthus martensii Karsch. It features a primary sequence typical of the, excitatory anti-insect toxins: two contiguous Cys residues (Cys37-Cys38), and a shifted location of the fourth disulfide bridges (Cys38-Cys64), and, demonstrates bioactivity characteristic of the excitatory beta-toxins., However, it is noteworthy that BmK-betaIT is not conserved with a, glutamate residue at the preceding position of the third Cys residue, and, is the first example having a non-glutamate residue at the relevant, position in the excitatory scorpion beta-toxin subfamily. The 3D structure, of BmK-betaIT is determined with 2D NMR spectroscopy and molecular, modeling. The solution structure of BmK-betaIT is closely similar to those, of BmK IT-AP and Bj-xtrIT, only distinct from the latter by lack of an, alpha(0)-helix. The surface functional patch comparison with those of BmK, IT-AP and Bj-xtrIT reveals their striking similarity in the spatial, arrangement. These results infer that the functional surface of, beta-toxins is composed of two binding regions and a functional site. The, main binding site is consisted of hydrophobic residues surrounding the, alpha(1)-helix and its preceding loop, which is common to all beta-type, scorpion toxins affecting Na(+) channels. The second binding site, which, determines the specificity of the toxin, locates at the C-terminus for, excitatory insect beta-toxin, while rests at the beta-sheet and its, linking loop for anti-mammal toxins. The functional site involved in the, voltage sensor-trapping model, which characterizes the function of all, beta-toxins, is the negatively charged residue Glu15.
+BmK-betaIT (previously named as Bm32-VI in the literature), an excitatory scorpion beta-toxin, is purified from the venom of the Chinese scorpion Buthus martensii Karsch. It features a primary sequence typical of the excitatory anti-insect toxins: two contiguous Cys residues (Cys37-Cys38) and a shifted location of the fourth disulfide bridges (Cys38-Cys64), and demonstrates bioactivity characteristic of the excitatory beta-toxins. However, it is noteworthy that BmK-betaIT is not conserved with a glutamate residue at the preceding position of the third Cys residue, and is the first example having a non-glutamate residue at the relevant position in the excitatory scorpion beta-toxin subfamily. The 3D structure of BmK-betaIT is determined with 2D NMR spectroscopy and molecular modeling. The solution structure of BmK-betaIT is closely similar to those of BmK IT-AP and Bj-xtrIT, only distinct from the latter by lack of an alpha(0)-helix. The surface functional patch comparison with those of BmK IT-AP and Bj-xtrIT reveals their striking similarity in the spatial arrangement. These results infer that the functional surface of beta-toxins is composed of two binding regions and a functional site. The main binding site is consisted of hydrophobic residues surrounding the alpha(1)-helix and its preceding loop, which is common to all beta-type scorpion toxins affecting Na(+) channels. The second binding site, which determines the specificity of the toxin, locates at the C-terminus for excitatory insect beta-toxin, while rests at the beta-sheet and its linking loop for anti-mammal toxins. The functional site involved in the voltage sensor-trapping model, which characterizes the function of all beta-toxins, is the negatively charged residue Glu15.
 ==About this Structure==
-WWN is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Mesobuthus_martensii Mesobuthus martensii]. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1WWN OCA].
+WWN is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Mesobuthus_martensii Mesobuthus martensii]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1WWN OCA].
 ==Reference==
@@ Line 22: / Line 22: @@
 [[Category: an excitatory scorpion toxin]]
-''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Wed Nov 21 05:43:19 2007''
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:48:52 2008''