1.45A resolution structure of SRPN18 from Anopheles gambiae

Experimental Data Snapshot

  • Resolution: 1.45 Å
  • R-Value Free: 0.185 
  • R-Value Work: 0.165 
  • R-Value Observed: 0.166 

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This is version 1.4 of the entry. See complete history


1.45 angstrom resolution structure of SRPN18 from the malaria vector Anopheles gambiae.

Meekins, D.A.Zhang, X.Battaile, K.P.Lovell, S.Michel, K.

(2016) Acta Crystallogr F Struct Biol Commun 72: 853-862

  • DOI: https://doi.org/10.1107/S2053230X16017854
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Serine protease inhibitors (serpins) in insects function within development, wound healing and immunity. The genome of the African malaria vector, Anopheles gambiae, encodes 23 distinct serpin proteins, several of which are implicated in disease-relevant physiological responses. A. gambiae serpin 18 (SRPN18) was previously categorized as non-inhibitory based on the sequence of its reactive-center loop (RCL), a region responsible for targeting and initiating protease inhibition. The crystal structure of A. gambiae SRPN18 was determined to a resolution of 1.45 Å, including nearly the entire RCL in one of the two molecules in the asymmetric unit. The structure reveals that the SRPN18 RCL is extremely short and constricted, a feature associated with noncanonical inhibitors or non-inhibitory serpin superfamily members. Furthermore, the SRPN18 RCL does not contain a suitable protease target site and contains a large number of prolines. The SRPN18 structure therefore reveals a unique RCL architecture among the highly conserved serpin fold.

  • Organizational Affiliation

    Division of Biology, Kansas State University, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B
382Anopheles gambiaeMutation(s): 0 
Gene Names: SRPN18AgaP_AGAP007691
Find proteins for A7UR55 (Anopheles gambiae)
Explore A7UR55 
Go to UniProtKB:  A7UR55
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupA7UR55
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.45 Å
  • R-Value Free: 0.185 
  • R-Value Work: 0.165 
  • R-Value Observed: 0.166 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 40.419α = 90
b = 87.485β = 90
c = 194.794γ = 90
Software Package:
Software NamePurpose
Aimlessdata scaling
PDB_EXTRACTdata extraction
XDSdata reduction

Structure Validation

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Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number
National Institutes of Health/National Institute Of Allergy and Infectious Diseases (NIH/NIAID)United States5R01AI095842

Revision History  (Full details and data files)

  • Version 1.0: 2016-09-14
    Type: Initial release
  • Version 1.1: 2016-12-14
    Changes: Database references
  • Version 1.2: 2017-09-13
    Changes: Author supporting evidence
  • Version 1.3: 2019-12-11
    Changes: Author supporting evidence
  • Version 1.4: 2023-09-27
    Changes: Data collection, Database references, Refinement description