Insights into Enzymatic Catalysis from Binding and Hydrolysis of Diadenosine Tetraphosphate by E. coli Adenylate Kinase.

Tischlik S, Oelker M, Rogne P, Sauer-Eriksson AE, Drescher M, Wolf-Watz M

Biochemistry 62 (15) 2238-2243 [2023-08-01; online 2023-07-07]

Adenylate kinases play a crucial role in cellular energy homeostasis through the interconversion of ATP, AMP, and ADP in all living organisms. Here, we explore how adenylate kinase (AdK) from Escherichia coli interacts with diadenosine tetraphosphate (AP4A), a putative alarmone associated with transcriptional regulation, stress, and DNA damage response. From a combination of EPR and NMR spectroscopy together with X-ray crystallography, we found that AdK interacts with AP4A with two distinct modes that occur on disparate time scales. First, AdK dynamically interconverts between open and closed states with equal weights in the presence of AP4A. On a much slower time scale, AdK hydrolyses AP4A, and we suggest that the dynamically accessed substrate-bound open AdK conformation enables this hydrolytic activity. The partitioning of the enzyme into open and closed states is discussed in relation to a recently proposed linkage between active site dynamics and collective conformational dynamics.

Swedish NMR Centre (SNC) [Service]

PubMed 37418448

DOI 10.1021/acs.biochem.3c00189

Crossref 10.1021/acs.biochem.3c00189

pmc: PMC10399197

Publications 9.5.0