Full-length nisin immunity protein NisI from Lactococcus lactis in a lipid-free form: crystallization and X-ray analysis

NisI is a lantibiotic-binding lipoprotein that is specific for nisin. Nisin-producing microorganisms use NisI as an immunity protein for self-protection against nisin. Here, the purification, crystallization and preliminary X-ray diffraction of full-length NisI from Lactobacillus lactis in a lipid-free form (NisI22-C) are reported. Importantly, reductive methylation of the lysine residues in NisI22-C was essential for initial crystallization. Only methylated NisI22-C crystallized. The optimized crystals of methylated NisI22-C were grown in 30 – 40   mM ammonium sulfate, 0.1   M sodium acetate pH 4.6, 16 – 18% PEG 4000 at 295   K and diffracted to 1.9   Å resolution. The crystal belonged to space group P212121, with unit-cell parameters a = 45.99, b = 76.67, c = 76.39   Å , α = β = γ = 90.0 ° . Assuming the presence of one molecule in the asymmetric unit, the estimated Matthews coefficient (VM) is 2.58   Å 3   Da − 1 and the estimated solvent content is 52.3%.

Source: Acta Crystallographica Section F - June 16, 2017 Category: Biochemistry Authors: Jeong, J.H. Ha, S.C. Tags: nisin lantibiotics immunity protein reductive methylation research communications Source Type: research