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Deacetylation of sialic acid by esterases potentiates pneumococcal neuraminidase activity for mucin utilization, colonization and virulence

Pneumococcal neuraminidase is a key enzyme for sequential deglycosylation of host glycans, and plays an important role in host survival, colonization, and pathogenesis of infections caused by Streptococcus pneumoniae. One of the factors that can affect the activity of neuraminidase is the amount and...

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Autores principales: Kahya, Hasan F., Andrew, Peter W., Yesilkaya, Hasan
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5352144/
https://www.ncbi.nlm.nih.gov/pubmed/28257499
http://dx.doi.org/10.1371/journal.ppat.1006263
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author Kahya, Hasan F.
Andrew, Peter W.
Yesilkaya, Hasan
author_facet Kahya, Hasan F.
Andrew, Peter W.
Yesilkaya, Hasan
author_sort Kahya, Hasan F.
collection PubMed
description Pneumococcal neuraminidase is a key enzyme for sequential deglycosylation of host glycans, and plays an important role in host survival, colonization, and pathogenesis of infections caused by Streptococcus pneumoniae. One of the factors that can affect the activity of neuraminidase is the amount and position of acetylation present in its substrate sialic acid. We hypothesised that pneumococcal esterases potentiate neuraminidase activity by removing acetylation from sialic acid, and that will have a major effect on pneumococcal survival on mucin, colonization, and virulence. These hypotheses were tested using isogenic mutants and recombinant esterases in microbiological, biochemical and in vivo assays. We found that pneumococcal esterase activity is encoded by at least four genes, SPD_0534 (EstA) was found to be responsible for the main esterase activity, and the pneumococcal esterases are specific for short acyl chains. Assay of esterase activity by using natural substrates showed that both the Axe and EstA esterases could use acetylated xylan and Bovine Sub-maxillary Mucin (BSM), a highly acetylated substrate, but only EstA was active against tributyrin (triglyceride). Incubation of BSM with either Axe or EstA led to the acetate release in a time and concentration dependent manner, and pre-treatment of BSM with either enzyme increased sialic acid release on subsequent exposure to neuraminidase A. qRT-PCR results showed that the expression level of estA and axe increased when exposed to BSM and in respiratory tissues. Mutation of estA alone or in combination with nanA (codes for neuraminidase A), or the replacement of its putative serine active site to alanine, reduced the pneumococcal ability to utilise BSM as a sole carbon source, sialic acid release, colonization, and virulence in a mouse model of pneumococcal pneumonia.
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spelling pubmed-53521442017-04-06 Deacetylation of sialic acid by esterases potentiates pneumococcal neuraminidase activity for mucin utilization, colonization and virulence Kahya, Hasan F. Andrew, Peter W. Yesilkaya, Hasan PLoS Pathog Research Article Pneumococcal neuraminidase is a key enzyme for sequential deglycosylation of host glycans, and plays an important role in host survival, colonization, and pathogenesis of infections caused by Streptococcus pneumoniae. One of the factors that can affect the activity of neuraminidase is the amount and position of acetylation present in its substrate sialic acid. We hypothesised that pneumococcal esterases potentiate neuraminidase activity by removing acetylation from sialic acid, and that will have a major effect on pneumococcal survival on mucin, colonization, and virulence. These hypotheses were tested using isogenic mutants and recombinant esterases in microbiological, biochemical and in vivo assays. We found that pneumococcal esterase activity is encoded by at least four genes, SPD_0534 (EstA) was found to be responsible for the main esterase activity, and the pneumococcal esterases are specific for short acyl chains. Assay of esterase activity by using natural substrates showed that both the Axe and EstA esterases could use acetylated xylan and Bovine Sub-maxillary Mucin (BSM), a highly acetylated substrate, but only EstA was active against tributyrin (triglyceride). Incubation of BSM with either Axe or EstA led to the acetate release in a time and concentration dependent manner, and pre-treatment of BSM with either enzyme increased sialic acid release on subsequent exposure to neuraminidase A. qRT-PCR results showed that the expression level of estA and axe increased when exposed to BSM and in respiratory tissues. Mutation of estA alone or in combination with nanA (codes for neuraminidase A), or the replacement of its putative serine active site to alanine, reduced the pneumococcal ability to utilise BSM as a sole carbon source, sialic acid release, colonization, and virulence in a mouse model of pneumococcal pneumonia. Public Library of Science 2017-03-03 /pmc/articles/PMC5352144/ /pubmed/28257499 http://dx.doi.org/10.1371/journal.ppat.1006263 Text en © 2017 Kahya et al http://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
spellingShingle Research Article
Kahya, Hasan F.
Andrew, Peter W.
Yesilkaya, Hasan
Deacetylation of sialic acid by esterases potentiates pneumococcal neuraminidase activity for mucin utilization, colonization and virulence
title Deacetylation of sialic acid by esterases potentiates pneumococcal neuraminidase activity for mucin utilization, colonization and virulence
title_full Deacetylation of sialic acid by esterases potentiates pneumococcal neuraminidase activity for mucin utilization, colonization and virulence
title_fullStr Deacetylation of sialic acid by esterases potentiates pneumococcal neuraminidase activity for mucin utilization, colonization and virulence
title_full_unstemmed Deacetylation of sialic acid by esterases potentiates pneumococcal neuraminidase activity for mucin utilization, colonization and virulence
title_short Deacetylation of sialic acid by esterases potentiates pneumococcal neuraminidase activity for mucin utilization, colonization and virulence
title_sort deacetylation of sialic acid by esterases potentiates pneumococcal neuraminidase activity for mucin utilization, colonization and virulence
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5352144/
https://www.ncbi.nlm.nih.gov/pubmed/28257499
http://dx.doi.org/10.1371/journal.ppat.1006263
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