Substrate specificity of 3-hydroxypicolinic acid unit in the viridogriseinbiosynthetic pathway

Abstract:

Abstract:［Objective］To explore the role of sgvS in the biosynthesis of 3-hydroxypicolinic acid moiety ofviridogrsein，and to analyze the substrate specificity of 3-hydroxypicolinic acid moiety in the viridogrsein biosynthetic pathway.［Methods］Through gene insertion inactivation and in trans complementation strategies，we obtained the gene inactivation mutant sgvS andits complementation mutant ΔsgvS:: sgvS． Meanwhile， we fed 3-hydroxypicolinic acid， picolinic acid， 2-piperidinecarboxylic acid，3-chloropyridinecarboxylic acid，4-chloropyridinecarboxylic acid，3，5-chloropyridinecarboxylic acid，nicotinic acid，2-chloronicotinic acid，2-fluoronicotinic acid acid，5-fluoronicotinic acid and 6-fluoronicotinic acid to the sgvSmutant，respectively．Thefermentation extracts were analyzed by HPLC.［Results］ sgvS mutant abolished the viridogrsein production; viridogrsein production was restored through in trans complementation of sgvS mutant or by feeding 3-hydroxypicolinic acid to the sgvS mutant．No new viridogrsein analogues were observed by feeding other above mentioned 3-hydroxypicolinic acid analogues tothe ΔsgvS mutant.［Conclusion］sgvS is necessary for the biosynthesis of 3- hydroxypicolinic acid moiety．The biosynthetic protein，SgvD1，activates 3-hydroxypicolinic acid，showing strict substrate specificity en route to the viridogrsein biosynthesis.