1GO9

Monitoring the structural Consequences of Phe12-->D-Phe12 and Leu15-->Aib15 substitution in h/r Corticotropin Releasing Hormone: Implications for Design of CRH antagonists.

Summary for 1GO9

• Entry DOI: 10.2210/pdb1go9/pdb
• Descriptor: CORTICOTROPIN RELEASING HORMONE (1 entity in total)
• Functional Keywords: hormone, corticotropin releasing hormone, synthetic analogues, solid phase synthesis, solutions structure
• Biological source: HOMO SAPIENS (HUMAN)
• Cellular location: Secreted : P06850
• Total number of polymer chains: 1
• Total formula weight: 4734.44

Authors

Spyroulias, G.A.,Papazacharias, S.,Pairas, G.,Cordopatis, P. (deposition date: 2001-10-20, release date: 2001-10-31, Last modification date: 2025-04-09)

Primary citation

Spyroulias, G.A.,Papazacharias, S.,Pairas, G.,Cordopatis, P.
Monitoring the Structural Consequences of Phe12-->D-Phe and Leu15-->Aib Substitution in Human/Rat Corticotropin Releasing Hormone. Implications for Design of Crh Antagonists.
Eur.J.Biochem., 269:6009-, 2002

PubMed Abstract: A new human/rat CRH analogue has been synthesized using the Fmoc/tBu solid-phase synthetic protocol. The sequence of the new peptide differs from the original in two positions, 12 and 15, at which the native amino acids l-phenylalanine 12 and l-leucine 15 have been replaced by the nonprotein amino acids d-phenylalanine and alpha-aminoisobutyric acid (Aib), respectively. The high resolution three-dimensional solution structure of [d-Phe12, Aib15]CRH has been determined by 688 distance constraints (656 meaningful NOE and 32 H-bonds distance limits) and 21 angle constraints. A family of 40 energy-minimized conformers was obtained with average rmsd of 0.39 +/- 0.16 A and 0.99 +/- 0.13 A for backbone and heavy atoms, respectively, and distance penalty functions of 0.42 +/- 0.03 A2. The NMR data acquired in a solvent system of water/trifluoroethanol (34%/66%, v/v) revealed that this 41-polypeptide adopts an almost linear helical structure in solution with helical content which reaches an 84% of the residues. Structural analysis confirmed the existence of two helical peptide fragments. The first was comprised of residues Ile6-Arg16 and the second of residues Glu20-Ile40, forming an angle of 34.2 degrees. The structural differences with respect to the native peptide have been identified in the region d-Phe12-Glu20 where double substitution at positions 12 and 15 seems to perturb the elements of the native 35-residue helix. These structural rearrangements promote non-native intramolecular interactions in the region of the molecule between either the hydrophobic side-chains of d-Phe12, Aib15 and Leu18, or the charged groups of the residue pairs Arg16-Glu20 and His13-Glu17 being responsible for changes in hormonal functionality. This CRH analogue currently exhibits lack of any activity.

PubMed: 12473096
DOI: 10.1046/J.1432-1033.2002.03278.X

Experimental method

SOLUTION NMR