1kma: Difference between revisions

[[Image:1kma.gif|left|200px]]

'''NMR Structure of the Domain-I of the Kazal-type Thrombin Inhibitor Dipetalin'''

The interaction of domains of the Kazal-type inhibitor protein dipetalin with the serine proteinases thrombin and trypsin is studied. The functional studies of the recombinantly expressed domains (Dip-I+II, Dip-I and Dip-II) allow the dissection of the thrombin inhibitory properties and the identification of Dip-I as a key contributor to thrombin/dipetalin complex stability and its inhibitory potency. Furthermore, Dip-I, but not Dip-II, forms a complex with trypsin resulting in an inhibition of the trypsin activity directed towards protein substrates. The high resolution NMR structure of the Dip-I domain is determined using multi-dimensional heteronuclear NMR spectroscopy. Dip-I exhibits the canonical Kazal-type fold with a central alpha-helix and a short two-stranded antiparallel beta-sheet. Molecular regions essential for inhibitor complex formation with thrombin and trypsin are identified. A comparison with molecular complexes of other Kazal-type thrombin and trypsin inhibitors by molecular modeling shows that the N-terminal segment of Dip-I fulfills the structural prerequisites for inhibitory interactions with either proteinase and explains the capacity of this single Kazal-type domain to interact with different proteinases.

1KMA is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Dipetalogaster_maximus Dipetalogaster maximus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1KMA OCA].  

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