Cloning and characterization of a sialidase from the filamentous fungus, Aspergillus fumigatus.
Abstract
A gene encoding a putative sialidase was identified in the genome of the opportunistic fungal pathogen, Aspergillus fumigatus. Computational analysis showed that this protein has Asp box and FRIP domains, it was predicted to have an extracellular localization, and a mass of 42 kDa, all of which are characteristics of sialidases. Structural modeling predicted a canonical 6-bladed beta-propeller structure with the model's highly conserved catalytic residues aligning well with those of an experimentally determined sialidase structure. The gene encoding the putative Af sialidase was cloned and expressed in Escherichia coli. Enzymatic characterization found that the enzyme was able to cleave the synthetic sialic acid substrate, 4-methylumbelliferyl alpha-D-N-acetylneuraminic acid (MUN), and had a pH optimum of 3.5. Further kinetic characterization using 4-methylumbelliferyl alpha-D-N-acetylneuraminylgalactopyranoside revealed that Af sialidase preferred alpha2-3-linked sialic acids over the alpha2-6 isomers. No trans-sialidase activity was detected. qPCR studies showed that exposure to MEM plus human serum induced expression. Purified Af sialidase released sialic acid from diverse substrates such as mucin, fetuin, epithelial cell gl...Continue Reading
References
Molecular cloning and characterization of NEU4, the fourth member of the human sialidase gene family
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Aspergillosis
Aspergillosis is the name given to a wide variety of diseases caused by infection by fungi of the genus Aspergillus. Aspergillosis occurs in chronic or acute forms which are clinically very distinct. Most cases of acute aspergillosis occur in patients with severely compromised immune systems. Chronic colonization or infection can cause complications in people with underlying respiratory illnesses. Discover the latest research on aspergillosis here.
Aspergillosis (ASM)
Aspergillosis is the name given to a wide variety of diseases caused by infection by fungi of the genus Aspergillus. Aspergillosis occurs in chronic or acute forms which are clinically very distinct. Most cases of acute aspergillosis occur in patients with severely compromised immune systems. Chronic colonization or infection can cause complications in people with underlying respiratory illnesses. Discover the latest research on aspergillosis here.