A New Type of Muconate Cycloisomerase from Rhodococcus rhodochrous Strain 89

I. P. Solyanikova¹, M. Schlömann², and L. A. Golovleva^1*

¹Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, Pushchino, Moscow Region, 142290 Russia; E-mail: golovleva@ibpm.serpukhov.su

²Interdisciplinary Ecological Center, Freiberg University of Mining and Technology, Leipziger str. 29, D-09599, Freiberg, Germany

^* To whom correspondence should be addressed.

Received November 22, 2000; Revision received April 5, 2001

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Muconate cycloisomerase (MCI) was purified from Rhodococcus rhodochrous 89 grown on phenol. The enzyme appears to contain two different type subunits with molecular masses 35.5 and 37 kD. The N-terminal amino acid sequence of both subunits showed more similarity to corresponding enzymes from gram-negative bacteria than to one from Rhodococcus opacus 1CP. MCI from R. rhodochrous 89, like analogous enzymes from gram-negative bacteria, can convert 2-chloromuconate (2-CM) with the formation of both, 2- and 5-chloromuconolactones (CML) as intermediates. Nevertheless, its unique ability to convert 5-CML to cis- but not to trans-dienelactone sets it apart from all known chloromuconate cycloisomerases from gram-negative and gram-positive bacteria.

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KEY WORDS: (chloro)muconate cycloisomerase, transformation, 2-chloromuconate, chloromuconolactones, dienelactones, Rhodococcus rhodochrous 89

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