Separation of isoforms of a Serratia marcescens endonuclease and cristallization of the enzyme

G. E. Bannikova, E. V. Blagova, V. P. Varlamov, E. Yu. Morgunova, A. A. Dementiev, S. V. Shlyapnikov

V. A. Engelhardt Institute of Molecular Biology Bioengineriya Centre, Moscow; Institute of Crystallography, Academy of Sciences of the USSR, Moscow; V. A. Engelhardt Institute of Molecular Biology, Academy of Sciences of the USSR, Moscow

Abstract: Two isoforms of an extracellular endonuclease, nuclease Sm_r and nuclease Sm_2r were isolated from the culture filtrate of Serratia marcescens strain B10 M1 by the ligand-exchange chromatography on iminodiacetate-agarose in Cu²⁺-form, and chromatography on phosphocellulose and DEAE-Toyopearl 650S. The pI for nucleases Sm₁ and Sm₂ were found to be 7,1 and 6,7, respectively. The amino acid analysis and N-terminal amino acid sequencing of the proteins showed a significant degree of homology between the enzymes. The secondary structure of nuclease Sm₂ was calculated. Crystals of nuclease Sm₂ were-obtained with the space group P2₁2₁2₁, a 69,0; b 106,7; c 74,8 A.

Russian Journal of Bioorganic Chemistry 1990, 16 (12):1678-1682

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