Investigating the mechanisms of secretion of the moonlighting proteins Enolase and Fructose-1, 6-Bisphosphate Aldolase in Neisseria meningitidis

Neisseria meningitidis is an obligate commensal of humans that mainly colonises the nasopharynx. It is also an important cause of serious diseases, such as meningitis and sepsis. N. meningitidis uses several secretion systems (type I, type Va, type Vb, and type Vc) for secreting proteins, which enab...

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Main Author: Atwah, Banan
Format: Thesis (University of Nottingham only)
Language:English
Published: 2019
Subjects:
Online Access:https://eprints.nottingham.ac.uk/56419/
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author Atwah, Banan
author_facet Atwah, Banan
author_sort Atwah, Banan
building Nottingham Research Data Repository
collection Online Access
description Neisseria meningitidis is an obligate commensal of humans that mainly colonises the nasopharynx. It is also an important cause of serious diseases, such as meningitis and sepsis. N. meningitidis uses several secretion systems (type I, type Va, type Vb, and type Vc) for secreting proteins, which enable the bacteria to modulate their cell surface and evade the human immune system. The moonlighting proteins fructose bis-1, 6-phosphate aldolase (FBA) and enolase were previously shown to localise to the surface of N. meningitidis. The mechanisms of secretion of both proteins were investigated in this study. Specifically, lysine residue 337 of enolase was substituted to investigate its role in secretion since in Escherichia coli mutation of the corresponding residue has been reported to decrease export efficiency. This study proposes that K337E substitution in meningococcal enolase causes a growth defect confirming an important functional role of this residue. However, its role in the localisation of the protein to the meningococcal cell surface is still not confirmed despite the several attempts to enhance enolase expression. The alanine residue 14 in the predicted cleavage site of the N-terminal region of FBA was substituted to investigate the role of the putative signal peptide in the surface localisation. Immunoblot analysis showed a reduction in FBA expression compared to the MC58ΔcbbA cbbAEct. Sub-cellular fractionation suggested that this mutation affected protein expression rather than its localisation to the meningococcal cell surface.
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spelling nottingham-564192025-02-28T14:27:55Z https://eprints.nottingham.ac.uk/56419/ Investigating the mechanisms of secretion of the moonlighting proteins Enolase and Fructose-1, 6-Bisphosphate Aldolase in Neisseria meningitidis Atwah, Banan Neisseria meningitidis is an obligate commensal of humans that mainly colonises the nasopharynx. It is also an important cause of serious diseases, such as meningitis and sepsis. N. meningitidis uses several secretion systems (type I, type Va, type Vb, and type Vc) for secreting proteins, which enable the bacteria to modulate their cell surface and evade the human immune system. The moonlighting proteins fructose bis-1, 6-phosphate aldolase (FBA) and enolase were previously shown to localise to the surface of N. meningitidis. The mechanisms of secretion of both proteins were investigated in this study. Specifically, lysine residue 337 of enolase was substituted to investigate its role in secretion since in Escherichia coli mutation of the corresponding residue has been reported to decrease export efficiency. This study proposes that K337E substitution in meningococcal enolase causes a growth defect confirming an important functional role of this residue. However, its role in the localisation of the protein to the meningococcal cell surface is still not confirmed despite the several attempts to enhance enolase expression. The alanine residue 14 in the predicted cleavage site of the N-terminal region of FBA was substituted to investigate the role of the putative signal peptide in the surface localisation. Immunoblot analysis showed a reduction in FBA expression compared to the MC58ΔcbbA cbbAEct. Sub-cellular fractionation suggested that this mutation affected protein expression rather than its localisation to the meningococcal cell surface. 2019-07-19 Thesis (University of Nottingham only) NonPeerReviewed application/pdf en arr https://eprints.nottingham.ac.uk/56419/1/Corrected%20PhD%20thesis%2C%20Banan%20Atwah%2C%204240906.pdf Atwah, Banan (2019) Investigating the mechanisms of secretion of the moonlighting proteins Enolase and Fructose-1, 6-Bisphosphate Aldolase in Neisseria meningitidis. PhD thesis, University of Nottingham. Neisseria meningitides; Moonlighting proteins; Secretion
spellingShingle Neisseria meningitides; Moonlighting proteins; Secretion
Atwah, Banan
Investigating the mechanisms of secretion of the moonlighting proteins Enolase and Fructose-1, 6-Bisphosphate Aldolase in Neisseria meningitidis
title Investigating the mechanisms of secretion of the moonlighting proteins Enolase and Fructose-1, 6-Bisphosphate Aldolase in Neisseria meningitidis
title_full Investigating the mechanisms of secretion of the moonlighting proteins Enolase and Fructose-1, 6-Bisphosphate Aldolase in Neisseria meningitidis
title_fullStr Investigating the mechanisms of secretion of the moonlighting proteins Enolase and Fructose-1, 6-Bisphosphate Aldolase in Neisseria meningitidis
title_full_unstemmed Investigating the mechanisms of secretion of the moonlighting proteins Enolase and Fructose-1, 6-Bisphosphate Aldolase in Neisseria meningitidis
title_short Investigating the mechanisms of secretion of the moonlighting proteins Enolase and Fructose-1, 6-Bisphosphate Aldolase in Neisseria meningitidis
title_sort investigating the mechanisms of secretion of the moonlighting proteins enolase and fructose-1, 6-bisphosphate aldolase in neisseria meningitidis
topic Neisseria meningitides; Moonlighting proteins; Secretion
url https://eprints.nottingham.ac.uk/56419/