1v4l: Difference between revisions
New page: left|200px<br /><applet load="1v4l" size="450" color="white" frame="true" align="right" spinBox="true" caption="1v4l, resolution 2.8Å" /> '''Crystal structure of ... |
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[[Image:1v4l.jpg|left|200px]]<br /><applet load="1v4l" size=" | [[Image:1v4l.jpg|left|200px]]<br /><applet load="1v4l" size="350" color="white" frame="true" align="right" spinBox="true" | ||
caption="1v4l, resolution 2.8Å" /> | caption="1v4l, resolution 2.8Å" /> | ||
'''Crystal structure of a platelet agglutination factor isolated from the venom of Taiwan habu (Trimeresurus mucrosquamatus)'''<br /> | '''Crystal structure of a platelet agglutination factor isolated from the venom of Taiwan habu (Trimeresurus mucrosquamatus)'''<br /> | ||
==Overview== | ==Overview== | ||
Platelet glycoprotein Ib (GPIb)-binding proteins (GPIb-BPs) from snake | Platelet glycoprotein Ib (GPIb)-binding proteins (GPIb-BPs) from snake venoms are usually C-type lectins, which target specific sites of GPIbalpha and elicit distinct effects on platelets. In the present paper, we report a tetrameric platelet-agglutinating factor (molecular mass 121.1 kDa), termed mucrocetin, purified from the venom of Taiwan habu (Trimeresurus mucrosquamatus ). Mucrocetin is a GPIbalpha agonist with a binding site distinct from that of flavocetin-A (a snake venom GPIbalpha antagonist) on GPIbalpha, in spite of the high sequence identity (94.6%) between the two venom lectins. The crystal structure of mucrocetin was solved and refined to 2.8 A (1 A=0.1 nm) resolution, which shows an interesting crystal packing of six-layer cylinders of doughnut-shaped molecules. The four alphabeta heterodimers are arranged in an unusual square-shaped ring stabilized by four interdimer 'head-to-tail' disulphide bridges. Detailed structural comparison between mucrocetin and flavocetin-A suggests that their disparate platelet effects are probably attributable to different charge distributions on the putative concave binding surface. A unique positively charged patch on the binding surface of mucrocetin, formed by Lys102, Lys108, Lys109 and Arg123 in the alpha-subunit coupled with Lys22, Lys102, Lys116 and Arg117 in the beta-subunit, appears to be the primary determinant of its platelet-agglutinating activity. Conceivably, this interesting venom factor may provide a useful tool to study platelet agglutination by binding to the GPIb-IX-V complex. | ||
==About this Structure== | ==About this Structure== | ||
1V4L is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Protobothrops_mucrosquamatus Protobothrops mucrosquamatus]. Full crystallographic information is available from [http:// | 1V4L is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Protobothrops_mucrosquamatus Protobothrops mucrosquamatus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1V4L OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: Protein complex]] | [[Category: Protein complex]] | ||
[[Category: Protobothrops mucrosquamatus]] | [[Category: Protobothrops mucrosquamatus]] | ||
[[Category: Huang, K | [[Category: Huang, K F.]] | ||
[[Category: Ko, T | [[Category: Ko, T P.]] | ||
[[Category: Wang, A | [[Category: Wang, A H.J.]] | ||
[[Category: lectin-like]] | [[Category: lectin-like]] | ||
[[Category: square-shaped ring]] | [[Category: square-shaped ring]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:31:24 2008'' | ||
Revision as of 13:31, 21 February 2008
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Crystal structure of a platelet agglutination factor isolated from the venom of Taiwan habu (Trimeresurus mucrosquamatus)
Overview
Platelet glycoprotein Ib (GPIb)-binding proteins (GPIb-BPs) from snake venoms are usually C-type lectins, which target specific sites of GPIbalpha and elicit distinct effects on platelets. In the present paper, we report a tetrameric platelet-agglutinating factor (molecular mass 121.1 kDa), termed mucrocetin, purified from the venom of Taiwan habu (Trimeresurus mucrosquamatus ). Mucrocetin is a GPIbalpha agonist with a binding site distinct from that of flavocetin-A (a snake venom GPIbalpha antagonist) on GPIbalpha, in spite of the high sequence identity (94.6%) between the two venom lectins. The crystal structure of mucrocetin was solved and refined to 2.8 A (1 A=0.1 nm) resolution, which shows an interesting crystal packing of six-layer cylinders of doughnut-shaped molecules. The four alphabeta heterodimers are arranged in an unusual square-shaped ring stabilized by four interdimer 'head-to-tail' disulphide bridges. Detailed structural comparison between mucrocetin and flavocetin-A suggests that their disparate platelet effects are probably attributable to different charge distributions on the putative concave binding surface. A unique positively charged patch on the binding surface of mucrocetin, formed by Lys102, Lys108, Lys109 and Arg123 in the alpha-subunit coupled with Lys22, Lys102, Lys116 and Arg117 in the beta-subunit, appears to be the primary determinant of its platelet-agglutinating activity. Conceivably, this interesting venom factor may provide a useful tool to study platelet agglutination by binding to the GPIb-IX-V complex.
About this Structure
1V4L is a Protein complex structure of sequences from Protobothrops mucrosquamatus. Full crystallographic information is available from OCA.
Reference
Crystal structure of a platelet-agglutinating factor isolated from the venom of Taiwan habu (Trimeresurus mucrosquamatus)., Huang KF, Ko TP, Hung CC, Chu J, Wang AH, Chiou SH, Biochem J. 2004 Mar 1;378(Pt 2):399-407. PMID:14613481
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