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1gmz

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==Overview==
==Overview==
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Snake venoms are rich sources of phospholipase A(2) homologues, both, active calcium-binding Asp49 enzymes and essentially inactive Lys49, proteins. They are responsible for multiple pharmacological effects, some, of which are dependent on catalytic activity and others of which are not., Here, the 2.4 A X-ray crystal structure of an active Asp49 phospholipase, A(2) from the venom of the snake Bothrops pirajai, refined to conventional, and free R values of 20.1 and 25.5%, respectively, is reported. Unusually, for phospholipases A(2), the dependence of the enzyme rate on the, substrate concentration is sigmoidal, implying cooperativity of substrate, binding. The unprecedented structural distortion seen for the, calcium-binding loop in the present structure may therefore be indicative, of a T-state enzyme. An explanation of the interaction between the, substrate-binding sites based on the canonical phospholipase A(2) dimer is, difficult. However, an alternative putative dimer interface identified in, the crystal lattice brings together the calcium-binding loops of, neighbouring molecules, along with the C-terminal regions which are, disulfide bonded to those loops, thereby offering a possible route of, communication between active sites.
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Snake venoms are rich sources of phospholipase A(2) homologues, both active calcium-binding Asp49 enzymes and essentially inactive Lys49 proteins. They are responsible for multiple pharmacological effects, some of which are dependent on catalytic activity and others of which are not. Here, the 2.4 A X-ray crystal structure of an active Asp49 phospholipase A(2) from the venom of the snake Bothrops pirajai, refined to conventional and free R values of 20.1 and 25.5%, respectively, is reported. Unusually for phospholipases A(2), the dependence of the enzyme rate on the substrate concentration is sigmoidal, implying cooperativity of substrate binding. The unprecedented structural distortion seen for the calcium-binding loop in the present structure may therefore be indicative of a T-state enzyme. An explanation of the interaction between the substrate-binding sites based on the canonical phospholipase A(2) dimer is difficult. However, an alternative putative dimer interface identified in the crystal lattice brings together the calcium-binding loops of neighbouring molecules, along with the C-terminal regions which are disulfide bonded to those loops, thereby offering a possible route of communication between active sites.
==About this Structure==
==About this Structure==
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[[Category: Phospholipase A(2)]]
[[Category: Phospholipase A(2)]]
[[Category: Single protein]]
[[Category: Single protein]]
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[[Category: Lee, W.H.]]
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[[Category: Lee, W H.]]
[[Category: Polikarpov, I.]]
[[Category: Polikarpov, I.]]
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[[Category: Rigden, D.J.]]
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[[Category: Rigden, D J.]]
[[Category: IPA]]
[[Category: IPA]]
[[Category: bothrops pirajai]]
[[Category: bothrops pirajai]]
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[[Category: x-ray structure]]
[[Category: x-ray structure]]
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''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Feb 3 09:41:06 2008''
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''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 12:51:51 2008''

Revision as of 10:51, 21 February 2008

Image:1gmz.gif

1gmz, resolution 2.40Å

Drag the structure with the mouse to rotate

CRYSTAL STRUCTURE OF THE D49 PHOSPHOLIPASE A2 PIRATOXIN III FROM BOTHROPS PIRAJAI.

Overview

Snake venoms are rich sources of phospholipase A(2) homologues, both active calcium-binding Asp49 enzymes and essentially inactive Lys49 proteins. They are responsible for multiple pharmacological effects, some of which are dependent on catalytic activity and others of which are not. Here, the 2.4 A X-ray crystal structure of an active Asp49 phospholipase A(2) from the venom of the snake Bothrops pirajai, refined to conventional and free R values of 20.1 and 25.5%, respectively, is reported. Unusually for phospholipases A(2), the dependence of the enzyme rate on the substrate concentration is sigmoidal, implying cooperativity of substrate binding. The unprecedented structural distortion seen for the calcium-binding loop in the present structure may therefore be indicative of a T-state enzyme. An explanation of the interaction between the substrate-binding sites based on the canonical phospholipase A(2) dimer is difficult. However, an alternative putative dimer interface identified in the crystal lattice brings together the calcium-binding loops of neighbouring molecules, along with the C-terminal regions which are disulfide bonded to those loops, thereby offering a possible route of communication between active sites.

About this Structure

1GMZ is a Single protein structure of sequence from Bothrops pirajai with as ligand. Active as Phospholipase A(2), with EC number 3.1.1.4 Known structural/functional Site: . Full crystallographic information is available from OCA.

Reference

The structure of the D49 phospholipase A2 piratoxin III from Bothrops pirajai reveals unprecedented structural displacement of the calcium-binding loop: possiblerelationship to cooperative substrate binding., Rigden DJ, Hwa LW, Marangoni S, Toyama MH, Polikarpov I, Acta Crystallogr D Biol Crystallogr. 2003 Feb;59(Pt 2):255-62. Epub 2003, Jan 23. PMID:12554936

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