Molecular cloning, characterization and expression analysis of two β-N-acetylhexosaminidase homologs ofCoccidioides posadasii

Multifaceted production strategies and applications of glucosamine: a comprehensive review

Glucosamine (GlcN) and its derivatives are in high demand and used in various applications such as food, a precursor for the biochemical synthesis of fuels and chemicals, drug delivery, cosmetics, and supplements. The vast number of applications attributed to GlcN has raised its demand, and there is a growing emphasis on developing production methods that are sustainable and economical. Several: physical, chemical, enzymatic, microbial fermentation, recombinant processing methods, and their combinations have been reported to produce GlcN from chitin and chitosan available from different sources, such as animals, plants, and fungi. In addition, genetic manipulation of certain organisms has significantly improved the quality and yield of GlcN compared to conventional processing methods. This review will summarize the chitin and chitosan-degrading enzymes found in various organisms and the expression systems that are widely used to produce GlcN. Furthermore, new developments and methods, including genetic and metabolic engineering of Escherichia coli and Bacillus subtilis to produce high titers of GlcN and GlcNAc will be reviewed. Moreover, other sources of glucosamine production viz. starch and inorganic ammonia will also be discussed. Finally, the conversion of GlcN to fuels and chemicals using catalytic and biochemical conversion will be discussed.

Identification, molecular characterization, and expression analysis of a DOMON-like type 9 carbohydrate-binding module domain-containing protein of Coccidioides posadasii

Previously, we investigated the effect of N-acetylglucosamine (GlcNAc) on Coccidioides posadasii chitinolytic enzymes during in vitro spherule-endospore (S/E) phase culture. During those studies, sodium dodecyl sulfatepolyacrylamide gel electrophoresis analysis of supernatants from S/E phase cultures grown in Converse medium with or without added GlcNAc revealed a ∼ 28-kDa band (CFP28), whose abundance was increased by GlcNAc in parallel with the chitinolytic enzymes. Mass spectrometry (MS) of the CFP28 band revealed peptides that matched an open reading frame found in the tentative consensus sequence, TC20325, retrieved from the Dana Farber Cancer Institute C. posadasii Gene Index Database. The TC20325 cDNA sequence was used to design internal primers based on MS peptides and a full-length cDNA was isolated using a combination of rapid amplification of cDNA ends and reverse transcription-polymerase chain reaction. The deduced amino acid sequence of the full-length cDNA consists of 231 amino acid residues with a 19 aa signal peptide. The mature protein has a calculated molecular mass of ∼ 24.5 kDa, a theoretical pI of 6.09, and consists of a single DOMON-like type 9 carbohydrate-binding module (CBM9-like-3) conserved domain. The protein shares the highest sequence similarity (≥57%) to hypothetical proteins from fungi within the Pezizomycotina subphylum of Ascomycota. Antiserum against a recombinant version of CFP28 recognized native CFP28 in S/E phase cells and culture supernatants. CFP28 mRNA and protein expression were detectable in S/E phase in Converse medium, but were increased in the presence of added GlcNAc. Purified native CFP28 reacted with pooled sera from patients with coccidioidomycosis.