PMID- 11842409 OWN - NLM STAT- MEDLINE DCOM- 20020418 LR - 20131121 IS - 0006-3525 (Print) IS - 0006-3525 (Linking) VI - 67 IP - 1 DP - 2002 TI - Changes in protein conformation and dynamics upon complex formation of brain-derived neurotrophic factor and its receptor: investigation by isotope-edited Fourier transform IR spectroscopy. PG - 10-9 AB - The interactions of brain-derived neurotrophic factor (BDNF) with the extracellular domain of its receptor (trkB) are investigated by employing isotope-edited Fourier transform IR (FTIR) spectroscopy. The protein secondary structures of individual BDNF and trkB in solutions are compared with those in their complex. The temperature dependence of the secondary structures of BDNF, trkB, and their complex is also investigated. Consistent with the crystal structure, we observe by FTIR spectroscopy that BDNF in solution contains predominantly beta strands (approximately 53%) and relatively low contents of other secondary structures including beta turns (approximately 16%), disordered structures (approximately 12%), and loops (approximately 18%) and is deficient in alpha helix. We also observe that trkB in solution contains mostly beta strands (52%) and little alpha helix. Conformational changes in both BDNF and trkB are observed upon complex formation. Specifically, upon binding of BDNF, the conformational changes in trkB appear to involve mostly beta turns and disordered structures while the majority of the beta-strand conformation remains unchanged. The IR data indicate that some of the disordered structures in the loop regions are likely converted to beta strands upon complex formation. The FTIR spectral data of BDNF, trkB, and their complex indicate that more amide NH groups of trkB undergo H-D exchange within the complex than those of the ligand-free receptor and that the thermal stability of trkB is decreased slightly upon binding of BDNF. The FT-Raman spectra of BDNF, trkB, and their complex show that the six intramolecular disulfide bonds of trkB undergo significant conformational changes upon binding of BDNF as a result of changes in the tertiary structure of trkB. Taken together, the FTIR and Raman data are consistent with the loosening of the tertiary structure of trkB upon binding of BDNF, which leads to more solvent exposure of the amide NH group and decreased thermal stability of trkB. This finding reveals an intriguing structural property of the neurotrophin ligand-receptor complex that is in contrast to other ligand-receptor complexes such as a cytokine-receptor complex that usually shows protection of the amide NH group and increased thermal stability upon complex formation. CI - Copyright 2002 John Wiley & Sons, Inc. FAU - Li, Tiansheng AU - Li T AD - Department of Pharmaceutics, Amgen Inc., Amgen Center, M/S 8-1-C, One Amgen Boulevard, Thousand Oaks, California 91320, USA. tli@amgen.com FAU - Talvenheimo, Jane AU - Talvenheimo J FAU - Zeni, Lisa AU - Zeni L FAU - Rosenfeld, Robert AU - Rosenfeld R FAU - Stearns, George AU - Stearns G FAU - Arakawa, Tsutomu AU - Arakawa T LA - eng PT - Comparative Study PT - Journal Article PL - United States TA - Biopolymers JT - Biopolymers JID - 0372525 RN - 0 (Brain-Derived Neurotrophic Factor) RN - 0 (Carbon Isotopes) RN - 0 (Culture Media, Conditioned) RN - 0 (Disulfides) RN - 0 (Nitrogen Isotopes) RN - 059QF0KO0R (Water) RN - AR09D82C7G (Deuterium) RN - EC 2.7.10.1 (Receptor, trkB) SB - IM MH - Animals MH - Brain-Derived Neurotrophic Factor/*chemistry/genetics/*metabolism MH - CHO Cells MH - Carbon Isotopes MH - Cricetinae MH - Culture Media, Conditioned MH - Deuterium/chemistry MH - Disulfides/chemistry MH - Escherichia coli/genetics MH - Humans MH - Nitrogen Isotopes MH - Protein Conformation MH - Protein Structure, Secondary MH - Protein Structure, Tertiary MH - Receptor, trkB/*chemistry/*metabolism MH - Spectroscopy, Fourier Transform Infrared/*methods MH - Temperature MH - Transfection MH - Water/chemistry EDAT- 2002/02/14 10:00 MHDA- 2002/04/19 10:01 CRDT- 2002/02/14 10:00 PHST- 2002/02/14 10:00 [pubmed] PHST- 2002/04/19 10:01 [medline] PHST- 2002/02/14 10:00 [entrez] AID - 10.1002/bip.10038 [pii] AID - 10.1002/bip.10038 [doi] PST - ppublish SO - Biopolymers. 2002;67(1):10-9. doi: 10.1002/bip.10038.