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Structural basis of noncanonical polyphenol oxidase activity in DLL-II: A lectin from Dolichos lablab.

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Relation http://ir.cftri.com/13870/
https://dx.doi.org/10.1002/bab.1653
 
Title Structural basis of noncanonical polyphenol
oxidase activity in DLL-II: A lectin from
Dolichos lablab.
 
Creator Yashavanth, L. Vishweshwaraiah
Abhishek, Acharya
Balaji, Prakash
 
Subject 05 Enzymes
22 Legumes-Pulses
 
Description Lectins known to possess an additional enzymatic function are
called leczymes. Previous studies reported a unique
polyphenol oxidase (PPO) activity in DLL-II—a leczyme from
Dolichos lablab. DLL-II shares a high sequence and structural
homology with DBL—another leczyme from Dolichos biflorus.
Incidentally, DBL possesses lipoxygenase activity, but not the
PPO activity. Legume lectins usually possess two
metal-binding sites A and B. Although these sites are
conserved in both DBL and DLL-II, site A in DLL-II is occupied
by Mn2+ and site B by Ca2+. In contrast, DLL-II binds Cu2+ and
Ca2+ at sites A and B, respectively. Here, investigating the
structural basis of PPO activity in DLL-II, we find that the PPO
activity is only dependent on Cu2+, but not Ca2+; and the lectin
activity requires only Ca2+. Further, our analysis suggests that
an alternative mechanism of PPO reaction may be operative in
DLL-II, which involves a mononuclear Cu2+ metal center; this is
in contrast to the bi-nuclear Cu2+ metal center commonly
observed in all PPOs. Importantly, structural and
computational approaches employed here, we hypothesize
possible PPO binding sites and the corresponding migration
channels for accessing the active site.
 
Date 2018
 
Type Article
PeerReviewed
 
Format pdf
 
Language en
 
Identifier http://ir.cftri.com/13870/1/Biotechnology_and_Applied_Biochemistry%202018%20701-717.pdf
Yashavanth, L. Vishweshwaraiah and Abhishek, Acharya and Balaji, Prakash (2018) Structural basis of noncanonical polyphenol oxidase activity in DLL-II: A lectin from Dolichos lablab. Biotechnology and Applied Biochemistry. pp. 701-717. ISSN 0885-4513