Premium
Molecular dynamics simulations reveal that tyrosine nitration leads to destabilization of CYP2B6 secondary structure
Author(s) -
Wilderman Ross,
Lee ChoonMyung,
Morgan Edward
Publication year - 2018
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2018.32.1_supplement.lb651
Subject(s) - chemistry , tyrosine , molecular dynamics , mutant , alanine scanning , nitration , cyp2b6 , residue (chemistry) , wild type , alanine , biophysics , protein secondary structure , biochemistry , computational chemistry , amino acid , enzyme , cytochrome p450 , biology , mutagenesis , gene , organic chemistry , cyp3a4
Post‐translational modification of proteins is a major mechanism for the control of cellular machinery. Nitric oxide stimulates ubiquitination and proteosomal degradation of CYP2B6 and CYP51, which is hypothesized to be due to tyrosine nitration. Alanine scanning of CYP2B6 residues indicated that Tyr190Ala, Tyr317Ala, and Tyr380Ala partially protected the enzyme from proteasomal degradation. Alignment of CYP2B sequences from the Cytochrome P450 Homepage revealed that residues 190, 317, and 380 are absolutely conserved tyrosines. Other residues that are tyrosine in CYP2B6 have less conservation across the aligned sequences. Molecular dynamics simulations of CYP2B6 wild‐type, Tyr‐to‐Ala mutants, and Tyr‐to‐3‐nitrotyrosine (NIY) mutants were performed. For most mutants, the protein was stable throughout the simulation period. However, CYP2B6 Tyr235Niy simulations collapsed due to the G‐helix unraveling. Simulation of this mutant was successful if the stabilizing mutations Tyr226His and Lys262Arg from the CYP2B6 crystallization construct were introduced into the protein. In general, mutant proteins behaved similarly to wild‐type CYP2B6 as measured by bond angles and lengths. However, mutating CYP2B6 decreased the solvent accessible surface area and volume while increasing the density of the protein across the simulation. While introduction of alanine did not have large effects on protein secondary structure, NIY caused large changes in protein secondary structural elements close to the residue in space. Furthermore, introduction of NIY at any residue decreased the magnitude of residue‐residue interaction correlations within CYP2B6. Overall, tyrosine nitration leads to secondary structure destabilization and compaction of CYP2B6. These results provide insight into effects of CYP2B6 tyrosine nitration that may lead to proteosomal degradation. Support or Funding Information NIEHS Grant # 003619 This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .