
@article {122349,
	title = {A dimer between monomers and hexamers-Oligomeric variations in glucosamine-6-phosphate deaminase family.},
	journal = {PLoS One},
	volume = {18},
	year = {2023},
	month = {2023},
	pages = {e0271654},
	abstract = {<p>In bacteria that live in hosts whose terminal sugar is a sialic acid, Glucosamine-6-phosphate deaminase (NagB) catalyzes the last step in converting sialic acid into Fructose-6-phosphate. These bacteria then use the Fructose-6-phosphate as an energy source. The enzyme NagB exists as a hexamer in Gram-negative bacteria and is allosterically regulated. In Gram-positive bacteria, it exists as a monomer and lacks allosteric regulation. Our identification of a dimeric Gram-negative bacterial NagB motivated us to characterize the structural basis of two closely related oligomeric forms. We report here the crystal structures of NagB from two Gram-negative pathogens, Haemophilus influenzae (Hi) and Pasturella multocida (Pm). The Hi-NagB is active as a hexamer, while Pm-NagB is active as a dimer. Both Hi-NagB and Pm-NagB contain the C-terminal helix implicated as essential for hexamer formation. The hexamer is described as a dimer of trimers. In the Pm-NagB dimer, the dimeric interface is conserved. The conservation of the dimer interface suggests that the three possible oligomeric forms of NagB are a monomer, a dimer, and a trimer of dimers. Computational modeling and MD simulations indicate that the residues at the trimeric interface have less stabilizing energy of oligomer formation than those in the dimer interface. We propose that Pm-NagB is the evolutionary link between the monomer and the hexamer forms.</p>
},
	keywords = {Aldose-Ketose Isomerases, Bacterial Proteins, Haemophilus influenzae, N-Acetylneuraminic Acid, Pasteurella multocida, Polymers},
	issn = {1932-6203},
	doi = {10.1371/journal.pone.0271654},
	author = {Srinivasachari, Sathya and Tiwari, Vikas R and Kharbanda, Tripti and Sowdamini, Ramanathan and Subramanian, Ramaswamy}
}
@article {81591,
	title = {Quaternary variations in the structural assembly of N-acetylglucosamine-6-phosphate deacetylase from Pasteurella multocida.},
	journal = {Proteins},
	year = {2020},
	month = {2020 Aug 31},
	abstract = {<p>N-acetylglucosamine 6-phosphate deacetylase (NagA) catalyzes the conversion of N-acetylglucosamine-6-phosphate to glucosamine-6-phosphate in amino sugar catabolism. This conversion is an essential step in the catabolism of sialic acid in several pathogenic bacteria, including Pasteurella multocida, and thus NagA is identified as a potential drug target. Here, we report the unique structural features of NagA from P. multocida (PmNagA) resolved to 1.95 {\r a}. PmNagA displays an altered quaternary architecture with unique interface interactions compared to its close homolog, the Escherichia coli NagA (EcNagA). We confirmed that the altered quaternary structure is not a crystallographic artefact using single particle electron cryo-microscopy. Analysis of the determined crystal structure reveals a set of hot-spot residues involved in novel interactions at the dimer-dimer interface. PmNagA binds to one Zn ion in the active site and demonstrates kinetic parameters comparable to other bacterial homologs. Kinetic studies reveal that at high substrate concentrations (~10-fold the K ), the tetrameric PmNagA displays hysteresis similar to its distant neighbor, the dimeric Staphylococcus aureus NagA (SaNagA). Our findings provide key information on structural and functional properties of NagA in P. multocida that could be utilized to design novel antibacterials. This article is protected by copyright. All rights reserved.</p>
},
	issn = {1097-0134},
	doi = {10.1002/prot.25996},
	author = {Manjunath, Lavanyaa and Coombes, David and Davies, James and Dhurandhar, Mugdha and Tiwari, Vikas R and Dobson, Renwick C J and Sowdhamini, R and Ramaswamy, S and Bose, Sucharita}
}
