Hypothetical Protein from Aspergillus niger contains Chromate Reductase Motifs

Abstract

Chromate reductase is an enzyme that converts toxic and carcinogenic Cr⁶⁺ to non-carcinogenic and less soluble Cr³⁺. A hypothetical protein (ref. XP-001388504.1) from Aspergillus niger has been identified as chromate reductase using bioinformatics techniques. The techniques involved Clustal W alignment and Basic Local Alignment Search Tool (BLAST). Using Clustal W alignment, the motifs VTPEYN and LKNAID were identified to be common among the different chromate reductase homologues aligned. The same motifs reappeared when the hypothetical protein was aligned with other chromate reductase homologues. The BLAST search also identified VTPEYN and LKNAID motifs on the A. niger genome, indicating the likelihood of the hypothetical protein being chromate reductase. The homologue was recovered as a putative chromate reductase gene encoded by an open reading frame of 2227 bp nucleotide sequence. These findings clearly demonstrate the hypothetical protein is likely to be chromate reductase.