UV- AND CD-SPECTRA OF RESTRICTION ENDONUCLEASE EcoRII AND DNA-METHYLASE EcoRII

VENYAMINOV S. Yu., KOSYKH V. G.*, KHOLODKOV O. A.*, BURYANOV Ya. I.*

Institute of Protein Research; *Institute of Biochemistry and Physiology of Microorganisms, Academy of Sciences of the USSR, Pushchino, Moscow Region

Abstract: UV- and CD-spectra of homogeneous enzymes have been measured. Extinction coefficients estimated from the UV-spectra are 0.97 for restriction endonuclease EcoRII at 279.5 nm and 1.17 for DNA-methylase EcoRII at 279 nm. As it follows from the CD spectra, both enzymes have a well developed tertiary structure and a highly ordered secondary structure, which consists of 22% α-helices, 64% β-structure and 9% bends for REcoRII and of 44% α-helices, 48% β-structure and 4% bends for MEcoRII. Restriction endonuclease denatures at 50 C, while DNA-methylase denatures at 45 C, with partial reversibility upon cooling.

Russian Journal of Bioorganic Chemistry 1990, 16 (1):47-51

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