1dpj: Difference between revisions

[[Image:1dpj.gif|left|200px]]<br /><applet load="1dpj" size="350" color="white" frame="true" align="right" spinBox="true"  

Aspartic proteinase A from yeast is specifically and potently inhibited by a small protein called IA3 from Saccharomyces cerevisiae. Although this inhibitor consists of 68 residues, we show that the inhibitory activity resides within the N-terminal half of the molecule. Structures solved at 2.2 and 1.8 A, respectively, for complexes of proteinase A with full-length IA3 and with a truncated form consisting only of residues 2-34, reveal an unprecedented mode of inhibitor-enzyme interactions. Neither form of the free inhibitor has detectable intrinsic secondary structure in solution. However, upon contact with the enzyme, residues 2-32 become ordered and adopt a near-perfect alpha-helical conformation. Thus, the proteinase acts as a folding template, stabilizing the helical conformation in the inhibitor, which results in the potent and specific blockage of the proteolytic activity.

1DPJ is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Saccharomyces_cerevisiae Saccharomyces cerevisiae] with <scene name='pdbligand=NAG:'>NAG</scene> and <scene name='pdbligand=SO4:'>SO4</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Saccharopepsin Saccharopepsin], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.4.23.25 3.4.23.25] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1DPJ OCA].  

[[Category: Dunn, B M.]]

[[Category: Lees, W E.]]

[[Category: Phylip, H L.]]

[[Category: Winther, J R.]]

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