1clv
From Proteopedia
(New page: 200px<br /><applet load="1clv" size="450" color="white" frame="true" align="right" spinBox="true" caption="1clv, resolution 2.00Å" /> '''YELLOW MEAL WORM ALP...) |
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| - | [[Image:1clv.gif|left|200px]]<br /><applet load="1clv" size=" | + | [[Image:1clv.gif|left|200px]]<br /><applet load="1clv" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1clv, resolution 2.00Å" /> | caption="1clv, resolution 2.00Å" /> | ||
'''YELLOW MEAL WORM ALPHA-AMYLASE IN COMPLEX WITH THE AMARANTH ALPHA-AMYLASE INHIBITOR'''<br /> | '''YELLOW MEAL WORM ALPHA-AMYLASE IN COMPLEX WITH THE AMARANTH ALPHA-AMYLASE INHIBITOR'''<br /> | ||
==Overview== | ==Overview== | ||
| - | BACKGROUND: alpha-Amylases constitute a family of enzymes that catalyze | + | BACKGROUND: alpha-Amylases constitute a family of enzymes that catalyze the hydrolysis of alpha-D-(1,4)-glucan linkages in starch and related polysaccharides. The Amaranth alpha-amylase inhibitor (AAI) specifically inhibits alpha-amylases from insects, but not from mammalian sources. AAI is the smallest proteinaceous alpha-amylase inhibitor described so far and has no known homologs in the sequence databases. Its mode of inhibition of alpha-amylases was unknown until now. RESULTS: The crystal structure of yellow meal worm alpha-amylase (TMA) in complex with AAI was determined at 2.0 A resolution. The overall fold of AAI, its three-stranded twisted beta sheet and the topology of its disulfide bonds identify it as a knottin-like protein. The inhibitor binds into the active-site groove of TMA, blocking the central four sugar-binding subsites. Residues from two AAI segments target the active-site residues of TMA. A comparison of the TMA-AAI complex with a modeled complex between porcine pancreatic alpha-amylase (PPA) and AAI identified six hydrogen bonds that can be formed only in the TMA-AAI complex. CONCLUSIONS: The binding of AAI to TMA presents a new inhibition mode for alpha-amylases. Due to its unique specificity towards insect alpha-amylases, AAI might represent a valuable tool for protecting crop plants from predatory insects. The close structural homology between AAI and 'knottins' opens new perspectives for the engineering of various novel activities onto the small scaffold of this group of proteins. |
==About this Structure== | ==About this Structure== | ||
| - | 1CLV is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Tenebrio_molitor Tenebrio molitor] with CA and CL as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Alpha-amylase Alpha-amylase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.1 3.2.1.1] Full crystallographic information is available from [http:// | + | 1CLV is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Tenebrio_molitor Tenebrio molitor] with <scene name='pdbligand=CA:'>CA</scene> and <scene name='pdbligand=CL:'>CL</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Alpha-amylase Alpha-amylase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.1 3.2.1.1] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1CLV OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Lozanov, V.]] | [[Category: Lozanov, V.]] | ||
[[Category: Patthy, A.]] | [[Category: Patthy, A.]] | ||
| - | [[Category: Pereira, P | + | [[Category: Pereira, P J.B.]] |
[[Category: Pongor, S.]] | [[Category: Pongor, S.]] | ||
[[Category: Strobl, S.]] | [[Category: Strobl, S.]] | ||
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[[Category: yellow meal worm]] | [[Category: yellow meal worm]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 12:07:23 2008'' |
Revision as of 10:07, 21 February 2008
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YELLOW MEAL WORM ALPHA-AMYLASE IN COMPLEX WITH THE AMARANTH ALPHA-AMYLASE INHIBITOR
Overview
BACKGROUND: alpha-Amylases constitute a family of enzymes that catalyze the hydrolysis of alpha-D-(1,4)-glucan linkages in starch and related polysaccharides. The Amaranth alpha-amylase inhibitor (AAI) specifically inhibits alpha-amylases from insects, but not from mammalian sources. AAI is the smallest proteinaceous alpha-amylase inhibitor described so far and has no known homologs in the sequence databases. Its mode of inhibition of alpha-amylases was unknown until now. RESULTS: The crystal structure of yellow meal worm alpha-amylase (TMA) in complex with AAI was determined at 2.0 A resolution. The overall fold of AAI, its three-stranded twisted beta sheet and the topology of its disulfide bonds identify it as a knottin-like protein. The inhibitor binds into the active-site groove of TMA, blocking the central four sugar-binding subsites. Residues from two AAI segments target the active-site residues of TMA. A comparison of the TMA-AAI complex with a modeled complex between porcine pancreatic alpha-amylase (PPA) and AAI identified six hydrogen bonds that can be formed only in the TMA-AAI complex. CONCLUSIONS: The binding of AAI to TMA presents a new inhibition mode for alpha-amylases. Due to its unique specificity towards insect alpha-amylases, AAI might represent a valuable tool for protecting crop plants from predatory insects. The close structural homology between AAI and 'knottins' opens new perspectives for the engineering of various novel activities onto the small scaffold of this group of proteins.
About this Structure
1CLV is a Protein complex structure of sequences from Tenebrio molitor with and as ligands. Active as Alpha-amylase, with EC number 3.2.1.1 Full crystallographic information is available from OCA.
Reference
Specific inhibition of insect alpha-amylases: yellow meal worm alpha-amylase in complex with the amaranth alpha-amylase inhibitor at 2.0 A resolution., Pereira PJ, Lozanov V, Patthy A, Huber R, Bode W, Pongor S, Strobl S, Structure. 1999 Sep 15;7(9):1079-88. PMID:10508777
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