Application of the small-angle x-ray scattering technique for the study of two-step equilibrium enzyme-substrate interactions

✍ Scribed by Fedor V. Tuzikov; Victor V. Zinoviev; Vladimir I. Vavilin; Ernst G. Malygin

• Publisher: Wiley (John Wiley & Sons)
• Year: 1998
• Tongue: English
• Weight: 708 KB
• Volume: 38
• Category: Article
• ISSN: 0006-3525
• DOI: 10.1002/(sici)1097-0282(199602)38:2<131::aid-bip1>3.0.co;2-w

✦ Synopsis

The .smull-anglc~ x-ray scattering (SAXS) technique is iised,fi,r the investigation of two-stage ~qiiilibriiim macromolecular interactions ofthe enzyme-substrate type in solution. Experimental procedures and methods of analyzing the duta obtained from SAXS have been elaborated. The algorithm .fiw the duta unul.v.sis allows one to determine the stoichiometric, equilibrium, and structural parameters of the enzyme-substrate complexes obtained. The thermodynumic characteristics. for the,fiwmation ofcomplexes ofdouble-stranded oligonucleotide with Eco dam methyltransferuse (MTase) have been determined and demonstrate a high cooperutivity of MTasc binding when the ternary complex containing the dimeric enzyme is,formed. The structiiralparameters (Rg, R,, semiaxes) have k e n determined,for free enzyme andpol.vnucleotides and of enzyme-substrate complexes, indicating structitrul rearrangements of the enzyme in the interaction with substrates. 0