Structural highlights
Function
NARJ_ECOLI Chaperone required for proper molybdenum cofactor insertion and final assembly of the membrane-bound respiratory nitrate reductase 1. Required for the insertion of the molybdenum into the apo-NarG subunit, maybe by keeping NarG in an appropriate competent-open conformation for the molybdenum cofactor insertion to occur. NarJ maintains the apoNarGH complex in a soluble state. Upon insertion of the molybdenum cofactor, NarJ seems to dissociate from the activated soluble NarGH complex, before its association with the NarI subunit on the membrane.[1] [2] [3] [4]
Publication Abstract from PubMed
In bacteria, NarJ plays an essential role as a redox enzyme maturation protein in the assembly of the nitrate reductase NarGHI by interacting with the N-terminal signal peptide of NarG to facilitate cofactor incorporation into NarG. The purpose of our research was to elucidate the exact mechanism of NarG signal peptide recognition by NarJ. We determined the structures of NarJ alone and in complex with the signal peptide of NarG via X-ray crystallography and verified the NarJ-NarG interaction through mutational, binding, and molecular dynamics simulation studies. NarJ adopts a curved alpha-helix bundle structure with a U-shaped hydrophobic groove on its concave side. This groove accommodates the signal peptide of NarG via a dual binding mode in which the left and right parts of the NarJ groove each interact with two consecutive hydrophobic residues from the N- and C-terminal regions of the NarG signal peptide, respectively, through shape and chemical complementarity. This binding is accompanied by unwinding of the helical structure of the NarG signal peptide and by stabilization of the NarG-binding loop of NarJ. We conclude that NarJ recognizes the NarG signal peptide through a complementary hydrophobic interaction mechanism that mediates a structural rearrangement.
Complementary hydrophobic interaction of the redox enzyme maturation protein NarJ with the signal peptide of the respiratory nitrate reductase NarG.,Song WS, Kim JH, Namgung B, Cho HY, Shin H, Oh HB, Ha NC, Yoon SI Int J Biol Macromol. 2024 Mar;262(Pt 1):129620. doi: , 10.1016/j.ijbiomac.2024.129620. Epub 2024 Jan 21. PMID:38262549[5]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Vergnes A, Pommier J, Toci R, Blasco F, Giordano G, Magalon A. NarJ chaperone binds on two distinct sites of the aponitrate reductase of Escherichia coli to coordinate molybdenum cofactor insertion and assembly. J Biol Chem. 2006 Jan 27;281(4):2170-6. PMID:16286471 doi:10.1074/jbc.M505902200
- ↑ Dubourdieu M, DeMoss JA. The narJ gene product is required for biogenesis of respiratory nitrate reductase in Escherichia coli. J Bacteriol. 1992 Feb;174(3):867-72. PMID:1732220 doi:10.1128/jb.174.3.867-872.1992
- ↑ Liu X, DeMoss JA. Characterization of NarJ, a system-specific chaperone required for nitrate reductase biogenesis in Escherichia coli. J Biol Chem. 1997 Sep 26;272(39):24266-71. PMID:9305880 doi:10.1074/jbc.272.39.24266
- ↑ Blasco F, Dos Santos JP, Magalon A, Frixon C, Guigliarelli B, Santini CL, Giordano G. NarJ is a specific chaperone required for molybdenum cofactor assembly in nitrate reductase A of Escherichia coli. Mol Microbiol. 1998 May;28(3):435-47. PMID:9632249 doi:10.1046/j.1365-2958.1998.00795.x
- ↑ Song WS, Kim JH, Namgung B, Cho HY, Shin H, Oh HB, Ha NC, Yoon SI. Complementary hydrophobic interaction of the redox enzyme maturation protein NarJ with the signal peptide of the respiratory nitrate reductase NarG. Int J Biol Macromol. 2024 Mar;262(Pt 1):129620. PMID:38262549 doi:10.1016/j.ijbiomac.2024.129620
