Structural characterization of two tandemly arranged DNA methyltransferase genes fromNeisseria gonorrhoeae MS11: N4-cytosine specific M.NgoMXV and nonfunctional 5-cytosine-type M.NgoMorf2P

Abstract

Two adjacent genes encoding DNA methyltransferases (MTases) of Neisseria gonorrhoeae MS11, an active N4-cytosine specific M. NgoMXV and an inactive 5-cytosine type M. NgoMorf2P, were cloned into Escherichia coli and sequenced. We analyzed the deduced amino acid sequence of both gene products and localized conserved regions characteristic for DNA MTases. Structure prediction, threading-derived alignments, and comparison with the common fold for DNA MTases allowed for construction of super-secondary and tertiary models for M.NgoMorf2P and M.NgoMXV, respectively. These models helped in identification of amino acids and structural elements essential for function of both enzymes. The implications of this putative structural model on the catalytic mechanism of M.NgoMXV and its possible relation to the common ancestor of modern DNA amino-MTases are also discussed.

Recent trends on the molecular biology of pneumococcal capsules, lytic enzymes, and bacteriophage

“…This observation strongly suggested that the corresponding genes had been incorporated from another source(s) rather than being the result of divergent evolution. Orfmet is a protein exhibiting a 73% identity with a truncated M. Ngo Morf2P C5MTase encoded by Neisseria gonorrhoeae MS11 [188], and 34% with the putative C5MTase coded by phage MAV1 of Mycoplasma arthritidis [189]. It is noteworthy that the Tn 5252 C5MTase was also detected in the genome of strain 949, the host of MM1 phage, demonstrating that this strain contains two similar C5MTases, one encoded by the phage and the other by the transposon [186].…”

Phylogenomic analysis of 16S rRNA:(guanine‐N2) methyltransferases suggests new family members and reveals highly conserved motifs and a domain structure similar to other nucleic acid amino‐methyltransferases

“…The residues functionally conserved between m 6 A, m 4 C and m 2 G MTases and implicated in binding of the cofactor and the target base are indicated by '¤'. In the lower panel the sequences of structurally characterized nucleic acid amino-MTases from the ␥-family (7): DNA:m 6 A MTase M.TaqI(18), DNA:m 4 C MTase M.NgoMXV(19), and RNA:m6 A MTase ErmAM(20) are shown for comparison. The consensus secondary structure is shown at the bottom.…”

Genome sequence of the temperate bacteriophage PH10 from Streptococcus oralis

“…It was hypothesized that this was caused by a frame shift [31]. Both frame shift mutations are located in a homopolymeric G-tract which contains 10 G residues in the PH10 sequence and 9 in the N. gonorrhoeae MS11 sequence, whereas bacteriophage VO1 sequence has 8 G residues.…”