1qfd
From Proteopedia
(New page: 200px<br /><applet load="1qfd" size="450" color="white" frame="true" align="right" spinBox="true" caption="1qfd" /> '''NMR SOLUTION STRUCTURE OF ALPHA-AMYLASE INHI...) |
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'''NMR SOLUTION STRUCTURE OF ALPHA-AMYLASE INHIBITOR (AAI)'''<br /> | '''NMR SOLUTION STRUCTURE OF ALPHA-AMYLASE INHIBITOR (AAI)'''<br /> | ||
==Overview== | ==Overview== | ||
| - | alpha-Amylase inhibitor (AAI), a 32-residue miniprotein from the Mexican | + | alpha-Amylase inhibitor (AAI), a 32-residue miniprotein from the Mexican crop plant amaranth (Amaranthus hypochondriacus), is the smallest known alpha-amylase inhibitor and is specific for insect alpha-amylases (Chagolla-Lopez, A., Blanco-Labra, A., Patthy, A., Sanchez, R., and Pongor, S. (1994) J. Biol. Chem. 269, 23675-23680). Its disulfide topology was confirmed by Edman degradation, and its three-dimensional solution structure was determined by two-dimensional 1H NMR spectroscopy at 500 MHz. Structural constraints (consisting of 348 nuclear Overhauser effect interproton distances, 8 backbone dihedral constraints, and 9 disulfide distance constraints) were used as an input to the X-PLOR program for simulated annealing and energy minimization calculations. The final set of 10 structures had a mean pairwise root mean square deviation of 0.32 A for the backbone atoms and 1.04 A for all heavy atoms. The structure of AAI consists of a short triple-stranded beta-sheet stabilized by three disulfide bonds, forming a typical knottin or inhibitor cystine knot fold found in miniproteins, which binds various macromolecular ligands. When the first intercystine segment of AAI (sequence IPKWNR) was inserted into a homologous position of the spider toxin Huwentoxin I, the resulting chimera showed a significant inhibitory activity, suggesting that this segment takes part in enzyme binding. |
==About this Structure== | ==About this Structure== | ||
| - | 1QFD is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Amaranthus_hypochondriacus Amaranthus hypochondriacus]. Full crystallographic information is available from [http:// | + | 1QFD is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Amaranthus_hypochondriacus Amaranthus hypochondriacus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1QFD OCA]. |
==Reference== | ==Reference== | ||
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[[Category: inhibitor]] | [[Category: inhibitor]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 14:38:57 2008'' |
Revision as of 12:38, 21 February 2008
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NMR SOLUTION STRUCTURE OF ALPHA-AMYLASE INHIBITOR (AAI)
Overview
alpha-Amylase inhibitor (AAI), a 32-residue miniprotein from the Mexican crop plant amaranth (Amaranthus hypochondriacus), is the smallest known alpha-amylase inhibitor and is specific for insect alpha-amylases (Chagolla-Lopez, A., Blanco-Labra, A., Patthy, A., Sanchez, R., and Pongor, S. (1994) J. Biol. Chem. 269, 23675-23680). Its disulfide topology was confirmed by Edman degradation, and its three-dimensional solution structure was determined by two-dimensional 1H NMR spectroscopy at 500 MHz. Structural constraints (consisting of 348 nuclear Overhauser effect interproton distances, 8 backbone dihedral constraints, and 9 disulfide distance constraints) were used as an input to the X-PLOR program for simulated annealing and energy minimization calculations. The final set of 10 structures had a mean pairwise root mean square deviation of 0.32 A for the backbone atoms and 1.04 A for all heavy atoms. The structure of AAI consists of a short triple-stranded beta-sheet stabilized by three disulfide bonds, forming a typical knottin or inhibitor cystine knot fold found in miniproteins, which binds various macromolecular ligands. When the first intercystine segment of AAI (sequence IPKWNR) was inserted into a homologous position of the spider toxin Huwentoxin I, the resulting chimera showed a significant inhibitory activity, suggesting that this segment takes part in enzyme binding.
About this Structure
1QFD is a Single protein structure of sequence from Amaranthus hypochondriacus. Full crystallographic information is available from OCA.
Reference
Solution structure of the major alpha-amylase inhibitor of the crop plant amaranth., Lu S, Deng P, Liu X, Luo J, Han R, Gu X, Liang S, Wang X, Li F, Lozanov V, Patthy A, Pongor S, J Biol Chem. 1999 Jul 16;274(29):20473-8. PMID:10400675
Page seeded by OCA on Thu Feb 21 14:38:57 2008
Categories: Amaranthus hypochondriacus | Single protein | Deng, P. | Feng, L. | Gu, X. | Han, R. | Liang, S. | Liu, X. | Lozanov, V. | Lu, S. | Luo, J. | Patthy, A. | Pongor, S. | Wang, X. | Inhibitor
