Substrate depolymerization pattern of Pseudomonas viridiflavaSF-312 pectate lyase

Abstract

Previously, other groups have reported that the limit product of polygalacturonic acid (PGA) depolymerization by Erwinia chrysanthemipectate lyase E (PLe) was predominantly an unsaturated oligogalacturonic acid with a degree of polymerization (DP) of two, while pectate lyase B and pectate lyase C produced a predominantly DP3 unsaturated oligogalacturonic acid. We have used high performance anion-exchange chromatography and pulsed amperometric detection to analyze oligogalacturonic acids released by Pseudomonas viridiflavaSF-312 PL, which, like Erwinia chrysanthemiPLe, can independently macerate host tissue. Our results demonstrated that DP 2 unsaturated oligogalacturonic acid was the major oligosaccharide released by Pseudomonas viridiflavaSF-312 PL. In contrast to Erwinia chrysanthemiPLe, we observed that DP 3 unsaturated oligogalacturonic acid was present in Pseudomonas viridiflavaPL reaction products during the first 200 min of PGA depolymerization. The limit product consisted of four times more DP 2 than DP 3 unsaturated oligogalacturonic acid. We also observed that small amounts of a series of oligogalacturonic acids lacking the 4,5-unsaturated nonreducing end function were released by Pseudomonas viridiflavaPL during the PGA depolymerization process. These results indicate that Pseudomonas viridiflavaPL utilizes a random endolytic PGA depolymerization mechanism, rather than the nonrandom endolytic mechanism utilized by Erwinia chrysanthemiPLe.