Genetic and Biochemical Analysis of Magnetosome Formation in Magnetospirillum gryphiswaldense

Abstract

Magnetite crystals produced by magnetotactic bacteria (MTB) have species-specific morphologies and sizes, which are mostly unknown from inorganic systems. This indicates that biomineralization in magnetosomes is a process under strict genetic control with regard to iron accumulation, to the deposition of magnetic crystals within a specific organelle, and to the intracellular assembly and alignment of such crystals into chain-like structures. During the past few years, our understanding of the molecular and genetic basis of magnetosome formation has improved substantially due to the increasing amount of genomic sequence data obtained from various MTB, and the development of advanced genetic techniques for their study. In this chapter we summarize our current knowledge of the genes and proteins that control magnetosome biomineralization in Magneto-spirillum gryphiswaldense, and provide an overview of the genomic analysis of MTB, with emphasis on the structure and organization of the genomic “magnetosome island” (MAI) identified in M. gryphiswaldense and other MTB. In addition, a model of magnetosome formation and magnetite biomineralization is described.