title: Probing the molecular determinant of the lipase-specific foldase Lif26 for the interaction with its cognate Lip26.
abstract: As a steric chaperone, the lipase-specific foldase Lif26 from Acinetobacter sp. XMZ-26 is required for correct folding of the lipase Lip26 in in vivo co-expression and in vitro refolding systems. Lif26 interacts with Lip26 as determined by yeast two hybrid assays in vivo and GST pull-down experiments in vitro. To study the molecular determinants of the interaction between Lif26 and Lip26, a homology model-based screening of residues, molecular dynamics (MD) simulation-based calculation of interaction energies, and site-directed mutagenesis to alter individual screened residues were applied. One conserved amino acid in the C-terminal mini-domain of Lif26, Arg332, was involved in the interaction with Lip26. Arg332 could not be replaced by any other residue, based on saturated site-directed mutagenesis, and it formed a conserved and stable salt bridge with Glu112 of Lip26, which may contribute to binding specificity. The residues surrounding Arg332, such as Trp288 in α9, likely stabilized Arg332 in the proper conformation for the interaction with Lip26.
authors.affiliation: Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, PR China. zheng_xm2012@126.com
authors.forename: Xiaomei
authors.initials: X
authors.lastname: Zheng
authors.forename: Jian
authors.initials: J
authors.lastname: Tian
authors.forename: Ningfeng
authors.initials: N
authors.lastname: Wu
authors.forename: Yunliu
authors.initials: Y
authors.lastname: Fan
mesh_terms: D000150:Acinetobacter / Q000201:enzymology*; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D016000:Cluster Analysis; D017124:Conserved Sequence; D006860:Hydrogen Bonding; D008049:Lipase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D056004:Molecular Dynamics Simulation; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs; D017433:Protein Structure, Secondary; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D040681:Structural Homology, Protein; D013816:Thermodynamics; D020798:Two-Hybrid System Techniques
chemical_list: D001426:Bacterial Proteins; D008049:Lipase; C504169:lipase foldase