1agn: Difference between revisions

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[[Image:1agn.gif|left|200px]]
[[Image:1agn.png|left|200px]]


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==Overview==
{{ABSTRACT_9228021}}
The structural determinants of substrate recognition in the human class IV, or sigmasigma, alcohol dehydrogenase (ADH) isoenzyme were examined through x-ray crystallography and site-directed mutagenesis. The crystal structure of sigmasigma ADH complexed with NAD+ and acetate was solved to 3-A resolution. The human beta1beta1 and sigmasigma ADH isoenzymes share 69% sequence identity and exhibit dramatically different kinetic properties. Differences in the amino acids at positions 57, 116, 141, 309, and 317 create a different topology within the sigmasigma substrate-binding pocket, relative to the beta1beta1 isoenzyme. The nicotinamide ring of the NAD(H) molecule, in the sigmasigma structure, appears to be twisted relative to its position in the beta1beta1 isoenzyme. In conjunction with movements of Thr-48 and Phe-93, this twist widens the substrate pocket in the vicinity of the catalytic zinc and may contribute to this isoenzyme's high Km for small substrates. The presence of Met-57, Met-141, and Phe-309 narrow the middle region of the sigmasigma substrate pocket and may explain the substantially decreased Km values with increased chain length of substrates in sigmasigma ADH. The kinetic properties of a mutant sigmasigma enzyme (sigma309L317A) suggest that widening the middle region of the substrate pocket increases Km by weakening the interactions between the enzyme and smaller substrates while not affecting the binding of longer alcohols, such as hexanol and retinol.


==About this Structure==
==About this Structure==
1AGN is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. The following page contains interesting information on the relation of 1AGN with [[http://pdb.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb13_1.html Alcohol Dehydrogenase]]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1AGN OCA].  
1AGN is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. The following page contains interesting information on the relation of 1AGN with [[http://pdb.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb13_1.html Alcohol Dehydrogenase]]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1AGN OCA].  
==Reference==
X-ray structure of human class IV sigmasigma alcohol dehydrogenase. Structural basis for substrate specificity., Xie P, Parsons SH, Speckhard DC, Bosron WF, Hurley TD, J Biol Chem. 1997 Jul 25;272(30):18558-63. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/9228021 9228021]
[[Category: Alcohol Dehydrogenase]]
[[Category: Alcohol Dehydrogenase]]
[[Category: Alcohol dehydrogenase]]
[[Category: Alcohol dehydrogenase]]
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[[Category: Xie, P.]]
[[Category: Xie, P.]]
[[Category: Oxidoreductase]]
[[Category: Oxidoreductase]]
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May  2 10:14:38 2008''
 
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Jun 26 17:03:01 2008''

Revision as of 17:03, 26 June 2008

File:1agn.png

Template:STRUCTURE 1agn

X-RAY STRUCTURE OF HUMAN SIGMA ALCOHOL DEHYDROGENASE


Template:ABSTRACT 9228021

About this StructureAbout this Structure

1AGN is a Single protein structure of sequence from Homo sapiens. The following page contains interesting information on the relation of 1AGN with [Alcohol Dehydrogenase]. Full crystallographic information is available from OCA.

Page seeded by OCA on Thu Jun 26 17:03:01 2008

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