TY - BOOK ID - 93579052 TI - Bioactive Conformation I AU - Peters, Thomas AU - SpringerLink (Online service) PY - 2007 SN - 9783540490784 PB - Berlin, Heidelberg Springer-Verlag Berlin Heidelberg DB - UniCat KW - Organic chemistry KW - organische chemie UR - https://www.unicat.be/uniCat?func=search&query=sysid:93579052 AB - Speci?c binding of a ligand to a receptor is a key step in a variety of biol- ical processes, such as immune reactions, enzyme cascades, or intracellular transport processes. The ligand-receptor terminology implies that the rec- tor molecule is signi?cantly larger than the ligand, and the term bioactive conformation usually characterizes the conformation of a ligand when it is bound to a receptor. In a more general sense, bioactive conformation applies toanymoleculeinabiologicallyrelevantboundstateregardlessofsizecons- erations. Mostofthecontributions tothisbookaddressligandsthat aremuch smaller than their receptors. X-ray crystallography and high resolution NMR spectroscopy are the two main experimental techniques used to study bioactive conformations. The- fore,the twovolumes ofthisbookcover approachesthat use either ofthetwo techniques, or a combination thereof. The combination of X-ray crystallog- phy and NMR spectroscopy is particularly useful when a crystal structure of areceptorprotein,butnotofthereceptorprotein-ligandcomplex,isavailable. Anumberofexperimentaltechniquestoanalyzethebioactiveconformationof aligandwithNMRarebasedontheobservationoftheresonancesignalsofthe free ligand that is in exchange with the bound ligand. Several chapters focus onsuchapproachesthat rangefromclassical transferredNOEexperiments, totransferreddipolarcouplings,toSTD(SaturationTransferDifference)NMR techniques. Incaseswhere tightbinding inthesub-nanomolar rangeprevents the analysis of the bioactive conformation via free ligand signals, the ligand- protein complex has to be analyzed with protein NMR-based techniques or by crystallography. Since this area has been the subject of many reviews and monographs it will not be covered here in particular detail. As a unifying theme, all contributions target the question of how molecular recognition of biologically active molecules is achieved on the atomic scale. ER -