Evolution and molecular mechanism of PitAs in iron transport of Streptococcus species.

Evolution and molecular mechanism of PitAs in iron transport of Streptococcus species.
J Inorg Biochem. 2018 Feb 10;182:113-123
Authors: Cao K, Zhang J, Miao XY, Wei QX, Zhao XL, He QY, Sun X
Abstract
Iron is an essential element for almost all bacteria. The iron ATP-binding cassette (ABC) transporters located on the cell membrane affects bacterial virulence and infection. Although a variety of Fe3+-transporters have been found in bacteria, their evolutionary processes are rarely studied. Pneumococcal iron ABC transporter (PitA), a highly conserved Fe3+-transporter in most pathogenic bacteria, influences the capsule formation and virulence of bacteria. However, multiple sequence alignment revealed that PitA is expressed in four different variants in bacteria, and the structural complexity of these variants increases progressively. To more efficiently import Fe3+ ions into bacterial cells, bacteria have evolved a fused PitA from two separately expressed PitA-1 (SPD_0227) and PitA-2 (SPD_0226) proteins. Further biochemical characterization indicated that both PitA-1 and PitA-2 have weaker Fe3+-binding ability than their protein complex. More importantly, Glutathione S-Transferase (GST) pull-down and isothermal titration calorimetry (ITC) detection showed that PitA-1 and PitA-2 interact with each other via Tyr111-Leu37, Asn112-Gln38, Asn103-Leu33, and Asn103-Thr34. Further molecular dynamics (MD) simulations demonstrated that this inter...

Source: Journal of Inorganic Biochemistry - February 10, 2018 Category: Biochemistry Authors: Cao K, Zhang J, Miao XY, Wei QX, Zhao XL, He QY, Sun X Tags: J Inorg Biochem Source Type: research