WITHDRAWN: Molecular Insight Into the Mutation Within Critical Zinc2+-Binding Site in the PAS Domain of WalK in Vancomycin-Intermediate Resistant Staphylococcus Aureus

Abstract

Vancomycin-intermediate resistant Staphylococcus aureus (VISA), one of the common causes of nosocomial infection, is developed by mutations, including in walKR, with unclear molecular mechanisms. Although studies have verified some of these mutations, there are a few studies to pay attention to the importance of molecular modeling of mutations. Here, the Sanger sequencing for comparing gene sequences of WlKR between a VISA and its parental strain revealed mutation WalK-H364R. Structural protein mapping showed that H364R was located in a functional zinc ion coordinating residue within the cytoplasmic Per-Arnt-Sim (PAS) domain. The structural and functional effects of this mutation were analyzed using molecular computational approaches based on the recently determined crystal structures of the PAS domain of S. aureus. WalK-H364R was predicted to destabilize protein and decrease WalK interactions with proteins and nucleic acids. The qRT-PCR method showed downregulation of walKR and WalKR-regulated autolysins, which verified the molecular computational results.Overall, WalK-H364R within a critical metal-coordinating site is linked to VISA development through the walKR gene expression changes as well as the destructive effects on protein.Therefore, molecular modeling can be provided detailed insight into the molecular mechanism of VISA development, in particular, where complementation experiments are not readily available.