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B6db references: 28931053

type Journal Article
authors Deng J, Gao H, Gao Z, Zhao H, Yang Y, Wu Q, Wu B, Jiang C
title Identification and molecular characterization of a metagenome-derived L-lysine decarboxylase gene from subtropical soil microorganisms
journal PLoS One
Activity 4.1.1.18
Family 4.1.1.18.b
sel selected
ui 28931053
year (2017)
volume 12
number 9
pages e0185060
 
keywords doi: 10.1371/journal.pone.0185060
abstract L-lysine decarboxylase (LDC, EC 4.1.1.18) is a key enzyme in the decarboxylation of L-lysine to 1,5-pentanediamine and efficiently contributes significance to biosynthetic capability. Metagenomic technology is a shortcut approach used to obtain new genes from uncultured microorganisms. In this study, a subtropical soil metagenomic library was constructed, and a putative LDC gene named ldc1E was isolated by function-based screening strategy through the indication of pH change by L-lysine decarboxylation. Amino acid sequence comparison and homology modeling indicated the close relation between Ldc1E and other putative LDCs. Multiple sequence alignment analysis revealed that Ldc1E contained a highly conserved motif Ser-X-His-Lys (Pxl), and molecular docking results showed that this motif was located in the active site and could combine with the cofactor pyridoxal 5'-phosphate. The ldc1E gene was subcloned into the pET-30a(+) vector and highly expressed in Escherichia coli BL21 (DE3) pLysS. The recombinant protein was purified to homogeneity. The maximum activity of Ldc1E occurred at pH 6.5 and 40C using L-lysine monohydrochloride as the substrate. Recombinant Ldc1E had apparent Km, kcat, and kcat/Km values of 1.080.16 mM, 5.090.63 s-1, and 4.73103 s-1 M-1, respectively. The specific activity of Ldc1E was 1.530.06 U mg-1 protein. Identifying a metagenome-derived LDC gene provided a rational reference for further gene modifications in industrial applications.
last changed 2017/09/26 10:23

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