
@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}
}
@article {86518,
	title = {Structure and Function of -Acetylmannosamine Kinases from Pathogenic Bacteria.},
	journal = {ACS Omega},
	volume = {5},
	year = {2020},
	month = {2020 Dec 08},
	pages = {30923-30936},
	abstract = {<p>Several pathogenic bacteria import and catabolize sialic acids as a source of carbon and nitrogen. Within the sialic acid catabolic pathway, the enzyme -acetylmannosamine kinase (NanK) catalyzes the phosphorylation of -acetylmannosamine to -acetylmannosamine-6-phosphate. This kinase belongs to the ROK superfamily of enzymes, which generally contain a conserved zinc-finger (ZnF) motif that is important for their structure and function. Previous structural studies have shown that the ZnF motif is absent in NanK of (-NanK), a Gram-negative bacterium that causes the gum disease gingivitis. However, the effect in loss of the ZnF motif on the kinase activity is unknown. Using kinetic and thermodynamic studies, we have studied the functional properties of -NanK to its substrates ManNAc and ATP, compared its activity with other ZnF motif-containing NanK enzymes from closely related Gram-negative pathogenic bacteria (-NanK), (-NanK), and (-NanK). Our studies show a 10-fold decrease in substrate binding affinity between NanK (apparent ≈ 700 μM) and ZnF motif-containing NanKs (apparent ≈ 60 μM). To understand the structural features that combat the loss of the ZnF motif in -NanK, we solved the crystal structures of functionally homologous ZnF motif-containing NanKs from and . Here, we report -NanK:unliganded, -NanK:AMPPNP, -NanK:ManNAc, -NanK:ManNAc, and -NanK:ManNAc-6P:ADP crystal structures. Structural comparisons of -NanK with -NanK, -NanK, and hMNK (human -acetylmannosamine kinase domain of UDP--acetylglucosamine-2-epimerase/-acetylmannosamine kinase, GNE) show that even though there is less sequence identity, they have high degree of structural similarity. Furthermore, our structural analyses highlight that the ZnF motif of -NanK is substituted by a set of hydrophobic residues, which forms a hydrophobic cluster that helps the proper orientation of ManNac in the active site. In summary, ZnF-containing and ZnF-lacking NanK enzymes from different Gram-negative pathogenic bacteria are functionally very similar but differ in their metal requirement. Our structural studies unveil the structural modifications in -NanK that compensate the loss of the ZnF motif in comparison to other NanK enzymes.</p>
},
	issn = {2470-1343},
	doi = {10.1021/acsomega.0c03699},
	author = {Gangi Setty, Thanuja and Sarkar, Arunabha and Coombes, David and Dobson, Renwick C J and Subramanian, Ramaswamy}
}
