TRANSPOSON MUTAGENESIS AND CLONING ANALYSIS OF MamZ GENE IN MAGNETOSPIRILLUM GRYPHISWALDENSE MSR-1

A magnetosome-deletion mutant strain of Magnetospirillum gryphiswaldense MSR-1, known as NM7, was obtained by means of a mini-Tn5 lac Z2 transposon insertion in conjugation experiments. A 4642-bp fragment containing a mini-Tn5 lac Z2 in NM7 was cloned through the sequential steps of digestion, self-ligation, and transformation, followed by complete sequencing. The results showed that this fragment contained two putative ORFs, designated ORF1 and ORF2, and the mini-Tn5 lac Z2 was inserted into the ORF2 sequence encoding the MamZ protein by using the BLAST program in NCBI. Experiments and software analysis indicated that the MamZ protein might possess both the iron transport and ferric-ion reduction capabilities, both of which activities participate in magnetosomes biometabolism in M. gryphiswaldense MSR-1.