Effect of zinc depletion on Streptococcus pneumoniae revealed by metalloproteomics

Abstract:

[Objective] This study is aimed to explore the effects of zinc deficiency and the corresponding adaptive growth of Streptococcus pneumoniae D39. [Methods] We extracted whole proteins from S. pneumoniae D39 cultured with or without zinc, performed two-dimensional electrophoresis (2-DE) combined with immobilized metal affinity chromatography (IMAC) and mass spectra (MS) to identify differentially expressed proteins. [Results] The 2-DE maps of whole cell proteins showed that 32 proteins were down-regulated and 35 up-regulated. These Zn2+ regulated proteins are mainly involved in carbohydrate metabolism, nucleotide metabolism, oxidation, proteins translation, synthesis and folding. The 2-DE maps of Zn2+-binding proteins by using Zn-IMAC separation exhibited 7 differentially expressed proteins, 1 down-regulated and 6 up-regulated. These Zn2+-binding proteins participate in the bacterial response to stress stimuli, proteins folding and amino acid metabolism. [Conclusion] To survive and infect the host, S. pneumoniae regulate many metabolic pathways mainly including carbohydrate metabolism and nucleotide metabolism under zinc deficiency. This study provides a theoretical basis for revealing the adaptive growth mechanism of bacteria in host environment with limited metal ions.