2PI6

Crystal structure of the sheep signalling glycoprotein (SPS-40) complex with 2-methyl-2-4-pentanediol at 1.65A resolution reveals specific binding characteristics of SPS-40


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.65 Å
  • R-Value Free: 0.217 
  • R-Value Work: 0.167 
  • R-Value Observed: 0.168 

wwPDB Validation   3D Report Full Report


This is version 2.1 of the entry. See complete history


Literature

Tryptophan as a three-way switch in regulating the function of the secretory signalling glycoprotein (SPS-40) from mammary glands: structure of SPS-40 complexed with 2-methylpentane-2,4-diol at 1.6 A resolution.

Sharma, P.Singh, N.Sinha, M.Sharma, S.Perbandt, M.Betzel, C.Kaur, P.Srinivasan, A.Singh, T.P.

(2009) Acta Crystallogr D Biol Crystallogr 65: 375-378

  • DOI: https://doi.org/10.1107/S0907444909002327
  • Primary Citation of Related Structures:  
    2PI6

  • PubMed Abstract: 

    The 40 kDa secretory signalling glycoprotein (SPS-40) is the first example with Trp78 in three functional orientations: (i) a resting state with a pinched conformation, (ii) a stacked conformation when bound to hexasaccharide and (iii) an obstructive conformation when inhibited by 2-methylpentane-2,4-diol (MPD). Trp78 is present in the core of the sugar-binding groove. The hexasaccharide N-acetylglucosamine (GlcNAc(6)) has been shown to bind to SPS-40. As a result of this, the conformation of Trp78 alters from the native pinched conformation (chi(1) = -65.5 degrees , chi(2,1) = -78.8 degrees , chi(2,2) = 97.5 degrees ) to the stacked conformation (chi(1) = -170.0 degrees , chi(2,1) = -114.3 degrees , chi(2,2) = 61.6 degrees ). Further binding experiments showed that saccharide binding does not occur in the presence of 20% MPD. The crystal structure determination of the complex of SPS-40 with MPD revealed the presence of two MPD molecules in the sugar-binding groove. The very tightly bound MPD molecules at subsites -2 and -1 induced an unexpected and a rarely observed conformation of Trp78 (chi(1) = 55.9 degrees , chi(2,1) = 90.2 degrees , chi(2,2) = -88.9 degrees ) which is termed an obstructive conformation. The binding of MPD molecules also twisted the side chains of Glu269 and Ile272 considerably. These residues are also part of the sugar-binding groove. The observed obstructive conformation of the side chain of Trp78 in the present structure is the exact opposite of the stacked conformation. This rarely observed conformation is stabilized by a number of hydrogen bonds between Trp78 and Asn79 through water molecules W49, W229, W269, W547 and W557.


  • Organizational Affiliation

    Department of Biophysics, All India Institute of Medical Sciences, New Delhi, India.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Chitinase-3-like protein 1361Ovis ariesMutation(s): 0 
UniProt
Find proteins for Q6TMG6 (Ovis aries)
Explore Q6TMG6 
Go to UniProtKB:  Q6TMG6
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ6TMG6
Sequence Annotations
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  • Reference Sequence
Oligosaccharides

Help

Entity ID: 2
MoleculeChains Length2D Diagram Glycosylation3D Interactions
alpha-D-mannopyranose-(1-4)-[alpha-D-mannopyranose-(1-6)]alpha-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose
B
5N-Glycosylation
Glycosylation Resources
GlyTouCan:  G42402GU
GlyCosmos:  G42402GU
GlyGen:  G42402GU
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.65 Å
  • R-Value Free: 0.217 
  • R-Value Work: 0.167 
  • R-Value Observed: 0.168 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 60.873α = 90
b = 66.415β = 90
c = 105.692γ = 90
Software Package:
Software NamePurpose
REFMACrefinement
HKL-2000data collection
DENZOdata reduction
SCALEPACKdata scaling
AMoREphasing

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2007-05-01
    Type: Initial release
  • Version 1.1: 2008-05-01
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Non-polymer description, Version format compliance
  • Version 2.0: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Advisory, Atomic model, Data collection, Derived calculations, Structure summary
  • Version 2.1: 2023-10-25
    Changes: Data collection, Database references, Refinement description, Structure summary