Exploration into the nickel ‘microcosmos’ in prokaryotes

• We summarize the latest progress on biocoordination chemistry of nickel.
• We include the most recent exploration on metalloproteome of nickel.
• We focus on structure and function of nickel-related proteins and enzymes.
• We explore some crosstalk between nickel and other metals for metallomic point of view.

Nickel participates in important biochemical processes in many prokaryotes. Nickel-requiring microorganisms thus have developed elaborate systems to maintain the homeostasis of nickel ions in cells by regulation of nickel uptake, storage and efflux utilization (as enzyme factors). Interestingly, many components are not limited to nickel homeostasis. Some of them evolve from other metal components, certain of them either adapt different functions upon associated metal ions or regulate different metal responses. This review summarizes the updated scenarios of nickel homeostasis in bacteria based on metalloproteomics, biocoordination chemistry and structural biology research, and also explores several examples of ‘crosstalk’ in the homeostasis of nickel and other metals.