Expression and In-silico Structural analysis of N-acetylglucosamine transporter, Ngt1 in model fungal pathogen, Candida albicans

Introduction

The commensal yeast, Candida albicans , has the enormous metabolic flexibility to utilize alternative carbon sources such as N-acetylglucosamine (GlcNAc) at the infection sites, thereby facilitating its adaptive strategies to colonize and thrive within diverse host niches. In Candia , GlcNAc specific transporter (Ngt1) imports GlcNAc at cell surface to induce signaling through the master regulator Ngs1 at the chromatin level. Thus, GlcNAc signaling is responsible for changing its habitat from commensal to pathogenic life style.

Objective

The current study aims at understanding the expression, structural and functional intricacies of Ngt1 that determines to GlcNAc sensitivity, specificity and its transport which is a prerogatory step in the GlcNAc signaling process in Candida.

Method

The 3-D structure of Ngt1 was predicted using AlphaFold. We have carried out docking studies using AutoDoc suite for native and Site directed mutant versions of Ngt1 with GlcNAc to determine role of critical amino acids and further, tunnel analysis to reveal the transport mechanism. These findings lead to the designing structure-based Ngt1blockers via virtual screening of natural compound libraries.

Results

Our docking studies on Ngt1 with GlcNAc revealed the useful insights in to mechanism and the role of critical amino acids (Ala 324, Ile 325, Tyr 329, and Asp 332) responsible for interaction. In our analysis, Asn 195, located within transmembrane helix and part of the UNC-93-like transmembrane regulatory protein domain, was identified as critical residue for GlcNAc interaction compared with other mutated residues. Interestingly, the tunnel analysis of Ngt1 transporter revealed presence potential pathways in Ngt1 protein for effective GlcNAc transport.

Conclusion

This study provides basic insights in to the structural aspects of Ngt1 and its interaction with GlcNAc that can be further explored for the development effective therapeutic agents for control of infection caused by the Candida.

Abstract Figure

Structural and functional analysis of Ngt1 protein.

Flow chart depicting Ngt1 3D modeling (AlphaFold2), docking studies Ngt1-wild type and SDM proteins with GlcNAc ligand, tunnel analysis reflecting transport of GlcNAc, and virtual screening to identify potential inhibitors (Brucine).