6CJ7

Crystal structure of Manduca sexta Serine protease inhibitor (Serpin)-12


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.60 Å
  • R-Value Free: 0.186 
  • R-Value Work: 0.163 
  • R-Value Observed: 0.164 

wwPDB Validation   3D Report Full Report


This is version 1.1 of the entry. See complete history


Literature

Manduca sexta serpin-12 controls the prophenoloxidase activation system in larval hemolymph.

Yang, F.Wang, Y.Sumathipala, N.Cao, X.Kanost, M.R.Jiang, H.

(2018) Insect Biochem Mol Biol 99: 27-36

  • DOI: 10.1016/j.ibmb.2018.05.004
  • Primary Citation of Related Structures:  
    6CJ7

  • PubMed Abstract: 
  • Insect prophenoloxidase activation is coordinated by a serine protease network, which is regulated by serine protease inhibitors of the serpin superfamily. The enzyme system also leads to proteolytic processing of a Spätzle precursor. Binding of Spätzle to a Toll receptor turns on a signaling pathway to induce the synthesis of defense proteins ...

    Insect prophenoloxidase activation is coordinated by a serine protease network, which is regulated by serine protease inhibitors of the serpin superfamily. The enzyme system also leads to proteolytic processing of a Spätzle precursor. Binding of Spätzle to a Toll receptor turns on a signaling pathway to induce the synthesis of defense proteins. Previous studies of the tobacco hornworm Manduca sexta have revealed key members of the protease cascade, which generates phenoloxidase for melanogenesis and Spätzle to induce immunity-related genes. Here we provide evidence that M. sexta serpin-12 regulates hemolymph protease-14 (HP14), an initiating protease of the cascade. This inhibitor, unlike the other serpins characterized in M. sexta, has an amino-terminal extension rich in hydrophilic residues and an unusual P1 residue (Leu 429 ) right before the scissile bond cleaved by a target protease. Serpins with similarities to serpin-12, including Drosophila Necrotic, were identified in a wide range of insects including flies, moths, wasps, beetles, and two hemimetabolous species. The serpin-12 mRNA is present at low, constitutive levels in larval fat body and hemocytes and becomes more abundant after an immune challenge. We produced the serpin-12 core domain (serpin-12ΔN) in insect cells and in Escherichia coli and demonstrated its inhibition of human cathepsin G, bovine α-chymotrypsin, and porcine pancreatic elastase. MALDI-TOF analysis of the reaction mixtures confirmed the predicted P1 residue of Leu 429 . Supplementation of larval plasma samples with the serpin-12ΔN decreased prophenoloxidase activation elicited by microbial cells and reduced the proteolytic activation of the protease precursors of HP6, HP8, PAPs, and other serine protease-related proteins. After incubation of plasma stimulated with peptidoglycan, a 72 kDa protein appeared, which was recognized by polyclonal antibodies against both serpin-12 and HP14, suggesting that a covalent serpin-protease complex formed when serpin-12 inhibited HP14. Together, these data suggest that M. sexta serpin-12 inhibits HP14 to regulate melanization and antimicrobial peptide induction.


    Organizational Affiliation

    Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK, 74078, USA. Electronic address: haobo.jiang@okstate.edu.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Serpin-12A390Manduca sextaMutation(s): 0 
UniProt
Find proteins for A0A3B6UET4 (Manduca sexta)
Explore A0A3B6UET4 
Go to UniProtKB:  A0A3B6UET4
Protein Feature View
Expand
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.60 Å
  • R-Value Free: 0.186 
  • R-Value Work: 0.163 
  • R-Value Observed: 0.164 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 40.997α = 90
b = 80.555β = 102.73
c = 55.125γ = 90
Software Package:
Software NamePurpose
PHENIXrefinement
HKL-3000data reduction
HKL-3000data scaling
PHENIXphasing

Structure Validation

View Full Validation Report




Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)United StatesGM58634
National Institutes of Health/National Institute Of Allergy and Infectious Diseases (NIH/NIAID)United StatesAI112662
National Institutes of Health/National Institute Of Allergy and Infectious Diseases (NIH/NIAID)United StatesAI133589

Revision History  (Full details and data files)

  • Version 1.0: 2018-07-04
    Type: Initial release
  • Version 1.1: 2019-12-18
    Changes: Author supporting evidence