1WSO

The solution structures of human Orexin-A


Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 100 
  • Conformers Submitted: 30 
  • Selection Criteria: target function 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Orexin-A is composed of a highly conserved C-terminal and a specific, hydrophilic N-terminal region, revealing the structural basis of specific recognition by the orexin-1 receptor

Takai, T.Takaya, T.Nakano, M.Akutsu, H.Nakagawa, A.Aimoto, S.Nagai, K.Ikegami, T.

(2006) J.Pept.Sci. 12: 443-454

  • DOI: 10.1002/psc.747

  • PubMed Abstract: 
  • Orexins-A and B, also called hypocretins-1 and 2, respectively, are neuropeptides that regulate feeding and sleep-wakefulness by binding to two orphan G protein-coupled receptors named orexin-1 (OX(1)R) and orexin-2 (OX(2)R). The sequences and functi ...

    Orexins-A and B, also called hypocretins-1 and 2, respectively, are neuropeptides that regulate feeding and sleep-wakefulness by binding to two orphan G protein-coupled receptors named orexin-1 (OX(1)R) and orexin-2 (OX(2)R). The sequences and functions of orexins-A and B are similar to each other, but the high sequence homology (68%) is limited in their C-terminal half regions (residues 15-33). The sequence of the N-terminal half region of orexin-A (residues 1-14), containing two disulfide bonds, is very different from that of orexin-B. The structure of orexin-A was determined using two-dimensional homonuclear and (15)N and (13)C natural abundance heteronuclear NMR experiments. Orexin-A had a compact conformation in the N-terminal half region, which contained a short helix (III:Cys6-Gln9) and was fixed by the two disulfide bonds, and a helix-turn-helix conformation (I:Leu16-Ala23 and II:Asn25-Thr32) in the remaining C-terminal half region. The C-terminal half region had both hydrophobic and hydrophilic residues, which existed on separate surfaces to provide an amphipathic character in helices I and II. The nine residues on the hydrophobic surface are also well conserved in orexin-B, and it was reported that the substitution of each of them with alanine resulted in a significant drop in the functional potency at the receptors. Therefore, we suggest that they form the surface responsible for the main hydrophobic interaction with the receptors. On the other hand, the residues on the hydrophilic surface, together with the hydrophilic residues in the N-terminal half region that form a cluster, are known to make only small contributions to the binding to the receptors through similar alanine-scan experiments. However, since our structure of orexin-A showed that large conformational and electrostatical differences between orexins-A and B were rather concentrated in the N-terminal half regions, we suggest that the region of orexin-A is important for the preference for orexin-A of OX(1)R.


    Organizational Affiliation

    Institute for Protein Research, Osaka University, Yamadaoka 3-2, Osaka, 565-0871, Japan.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Orexin-A
A
34Homo sapiensMutation(s): 1 
Gene Names: HCRT (OX, PPORX, PPOX)
Find proteins for O43612 (Homo sapiens)
Go to Gene View: HCRT
Go to UniProtKB:  O43612
Small Molecules
Modified Residues  2 Unique
IDChainsTypeFormula2D DiagramParent
NH2
Query on NH2
A
NON-POLYMERH2 N

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PCA
Query on PCA
A
L-PEPTIDE LINKINGC5 H7 N O3GLU
Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 100 
  • Conformers Submitted: 30 
  • Selection Criteria: target function 
  • Olderado: 1WSO Olderado

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

  • Deposited Date: 2004-11-08 
  • Released Date: 2004-11-30 
  • Deposition Author(s): Ikegami, T., Takai, T.

Revision History 

  • Version 1.0: 2004-11-30
    Type: Initial release
  • Version 1.1: 2008-04-30
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance