Biological activity is governed by the timely redistribution of molecular interactions, and static structural snapshots often appear insufficient to provide the molecular determinants that choreograph communication. This conundrum applies to multidomain enzymatic systems called nonribosomal peptide synthetases (NRPSs), which assemble simple substrates into complex metabolites, where a dynamic domain organization challenges rational design to produce new pharmaceuticals. Using a nuclear magnetic resonance (NMR) atomic-level readout of biochemical transformations, we demonstrate that global structural fluctuations help promote substrate-dependent communication and allosteric responses, and impeding these global dynamics by a point-site mutation hampers allostery and molecular recognition. Our results establish global structural dynamics as sensors of molecular events that can remodel domain interactions, and they provide new perspectives on mechanisms of allostery, protein communication, and NRPS synthesis.

Structural biology is the foundation for deriving molecular mechanisms, where snapshots of macromolecules and binding partners inform on mutations that test or modify function. However, frequently, the impact of mutations violates the underpinnings of structural models, and mechanisms become cryptic. This conundrum applies to multidomain enzymatic systems called nonribosomal peptide synthetases (NRPSs), which assemble simple substrates into complex metabolites often with pharmaceutical properties. Engineering NRPSs can generate new pharmaceuticals ^1-3 but a dynamic domain organization challenges rational design. ^4-8 Using nuclear magnetic resonance (NMR), we determined the solution structure of a 52 kDa cyclization domain and demonstrate that global intra-domain dynamics enable sensing of substrates tethered to partner domains and draw an allosteric response encompassing the enzyme’s buried active site and two binding sites 40 Å apart. We show that a point-site mutation that impedes the domain dynamics globally hampers the allosteric response. We demonstrate this mechanism through NMR experiments that provide atomic-level read-outs of allosteric responses during biochemical transformations in situ . Our results establish global structural dynamics as sensors of molecular events that can remodel domain interactions and illustrate the need for integrating structural dynamics explicitly when deriving molecular mechanisms through mutagenesis and structural biology.

Once a protein of relative obscurity, inositol polyphosphate multikinase (IPMK) emerged as a versatile and indispensable enzyme in cellular biology. With dual inositol and lipid kinase activities, IPMK generates pivotal signaling molecules such as InsP4 (inositol tetraphosphate), InsP5 (inositol pentaphosphate), and PIP3 (phosphoinositide 3,4,5-trisphosphate), positioning it as a critical regulator of cellular mechanisms. Initially identified in yeast and later recognized as essential for mammalian embryonic development, IPMK has transitioned from a niche interest to a focal point in studies of nutrient sensing, growth factor signaling, mRNA transport, and transcription regulation. Over two decades, multidisciplinary research has unveiled its far-reaching biological roles and implications in diverse diseases, including neurodegeneration, cancer, and inflammation. This review charts IPMK’s journey from obscurity to prominence, examining its structure–function relationships, cellular roles, and emerging physiological impacts, while highlighting its potential as a therapeutic target in human health and disease.