Identification and subcellular localization of a novel Cu,Zn superoxide dismutase of Mycobacterium tuberculosis

AbstractPeriplasmic copper, zinc superoxide dismutases (Cu,ZnSOD) of several Gram-negative pathogens have been shown to play an important role in protection against exogenous superoxide radicals and in determining virulence of the pathogens. Here we report the cloning and characterization of the sodC gene, encoding Cu,ZnSOD, from the Gram-positive Mycobacterium tuberculosis. The predicted protein sequence contains 240 amino acids with a putative signal peptide at the N-terminus and shows ∼25% identity to other bacterial sodC. Recombinant proteins of a full-length sodC and a truncated form lacking the putative signal peptide were overexpressed in Escherichia coli and affinity purified. Renatured recombinant M. tuberculosis sodC protein possessed characteristics of a Cu,ZnSOD. Immunoblotting with an antiserum against the recombinant M. tuberculosis Cu,ZnSOD allowed detection of a single polypeptide in the lysate of M. tuberculosis. This polypeptide has a similar size as the recombinant protein without the putative signal peptide indicating that the endogenous Cu,ZnSOD in M. tuberculosis might be processed and secreted. Furthermore, immunogold electron microscopic image showed that Cu,ZnSOD is located in the periphery of M. tuberculosis. The enzymatic activity and subcellular localization of this novel Cu,ZnSOD suggest that it may play a role in determining virulence of M. tuberculosis

The tetra-nucleotide haplotype frequencies (HF) of the DAO gene and their associations with schizophrenia in the original and replicated samples.

<p>The tetra-nucleotide haplotype frequencies (HF) of the DAO gene and their associations with schizophrenia in the original and replicated samples.</p

Genetic associations of CGTC and AAGC tetra-nucleotide haplotypes of DAO in subgroups of schizophrenia with or without impairments in sustained attention and executive function.

<p>Genetic associations of CGTC and AAGC tetra-nucleotide haplotypes of DAO in subgroups of schizophrenia with or without impairments in sustained attention and executive function.</p

The sequenced regions of DAO in this study.

<p>DAO genetic sequencing regions (gray box) are displayed throughout the promoter (pro), and 11 exons (E) (black box). These sequenced regions include the transcripts (T) and variants (V) of expressed sequence tags, the highly conserved region (CR) and the previously significant disease-associated haplotype region (HR). The primer pairs for all sequencing regions are presented in Table A in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0150435#pone.0150435.s002" target="_blank">S2 File</a>. The SNPs of rs11114083, rs2070586, rs2070587, and rs55944529 genotyped in this study are indicated within the genetic region.</p

Differential DAO expression for genotypes of rs55944529.

<p>The transcriptional DAO expression is measured by real-time RT-PCR in the EBV-transformed lymphoblasts of 126 subjects. The relative DAO expressions for subjects with CC (n = 88) and CT (n = 26) genotypes, are significantly higher than that of TT genotype (n = 12) (Z = 2.17, df = 125, p = 0.029, using Wilcoxon two-sample test). Data are presented as mean ± SD.</p

Single locus association analysis of the five SNPs of DAO selected from the direct sequencing results in the original and replicated samples.

<p>Single locus association analysis of the five SNPs of DAO selected from the direct sequencing results in the original and replicated samples.</p