The developmentally regulated Aspergillus nidulans wA gene encodes a polypeptide homologous to polyketide and fatty acid synthases

Abstract

The Aspergillus nidulans wA gene is required for synthesis of a green pigment present in the walls of mature asexual spores (conidia); wA mutants produce colorless (white) conidia. We determined the transcriptional structure and DNA sequence of the wA gene. wA consists of 5 exons separated by short (40-60 bp) introns. The processed transcript has the potential to encode a protein consisting of 1986 amino acid residues. The predicted WA polypeptide showed extensive sequence similarities with bacterial and fungal polyketide synthases and vertebrate fatty acid synthases, particularly within conserved active sites. Properties of the yellow conidial wall pigment intermediate suggest that it is a polyketide rather than a fatty acid. It is therefore likely that wA encodes all or part of a polyketide synthase involved in the formation of this pigment intermediate.

Sequence around the 159 region of the Bacillus subtilis genome: the pksX locus spans 33{middle dot}6 kb

“…Even more striking was the finding of a significantly high identity score (BLASTN probability of 6.9 x between SDPVFST and the w A gene of Aspergillzis nidzilans, a eukaryotic gene encoding a polyketide or fatty acid synthase (Mayorga & Timberlake, 1992). As reported in Table 1, three long stretches of SDPVFST, corresponding to the aforementioned three repeated sequences, have high identity to a coding region, exon 3, of w A .…”

Analysis of Modular-iterative Mixed Biosynthesis of Lankacidin by Heterologous Expression and Gene Fusion

“…Therefore, in the generation process of the lkc-PKS genes, the KS gene was fused with other genes in a unique order, while the AT and DH genes were not fused and remained as separate genes. The tandem alignment of two ACP domains was also found in the albicidin PKS [18] and several fungal type-I PKSs, for example, WA for naphtopyrone [19,20] and StcA for sterigmatocystin [21]. Huang et al [18] proposed that the second ACP domain in the albicidin PKS serves as a waiting position for growing chains to facilitate iterative condensation, although no experimental evidence was provided.…”

Functional replacement of the ketosynthase domain of FUM1 for the biosynthesis of fumonisins, a group of fungal reduced polyketides

“…This approach has been used to study the biosynthesis of fungal aromatic polyketides in the recent years. For example, Watanabe and Ebizuka [30] constructed a chimeric PKS composed of domains from wA gene in A. nidulans [18] and pks1 gene in Colletotrichum langenarium [26]. These two genes code for PKSs synthesizing a heptaketide and a pentaketide, respectively.…”

“…The column was Alltima C18LL (5 μ, 250 × 4.6 mm i.d., Alltech, Deerfi eld, IL, USA), and the experimental conditions were the same as described previously [5]. A RFC 18 Vydac MassSpec column (5 μ, 250 × 1 mm i.d., Vydac TM ) was used in the LC-ESMS analysis. All positive electrospray spectra were acquired using a Q-Tof Mass spectrometer (Micromass, Manchester, UK).…”