8AND | pdb_00008and

Domain swapped dimer of smolstatin (stefin) from Sphaerospora molnari

• PDB DOI: https://doi.org/10.2210/pdb8AND/pdb

• Classification: HYDROLASE INHIBITOR
• Organism(s): Sphaerospora molnari
• Expression System: Escherichia coli
• Mutation(s): No 


• Deposited: 2022-08-05 Released: 2024-04-17 
• Deposition Author(s): Havlickova, P., Bartosova-Sojkova, P., Sojka, D., Kascakova, B., Gavira, J.A., Kuta Smatanova, I.
• Funding Organization(s): Grant Agency of the Czech Republic, European Regional Development Fund

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 1.99 Å
• R-Value Free: 
  0.245 (Depositor), 0.251 (DCC) 
• R-Value Work: 
  0.199 (Depositor), 0.202 (DCC) 

Starting Model: in silico

Literature

Smolstatin1, a unique cystatin-like stefin of Sphaerospora molnari, is essential for parasite development

Bartosova-Sojkova, P., Dobai, T., Kyslik, J., Havlickova, P., Vancova, M., Picard-Sanchez, M.A., Qadiri, S.S.N., Martins, L.A., Urbanova, V., Kosakyan, A., Bily, T., Kale, D., Kotal, J., Chan, J.T.H., Korytar, T., Ludwig, J., Smatanova, I.K., Holzer, A.S., Sojka, D.

(2026) Curr Res Microb Sci : 100611

• DOI: https://doi.org/10.1016/j.crmicr.2026.100611

Biological Assembly 1  

Global Symmetry: Cyclic - C2  (Explore in 3D)
Global Stoichiometry: Homo 2-mer - A2 

Biological assembly 1 assigned by authors and generated by PISA (software)

Biological Assembly Evidence: native gel electrophoresis

Macromolecule Content 

• Total Structure Weight: 23.02 kDa 
• Atom Count: 1,645 
• Modeled Residue Count: 181 
• Deposited Residue Count: 200 
• Unique protein chains: 1

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Smolstatin	A [auth AAA], B [auth BBB]	100	Sphaerospora molnari	Mutation(s): 0

Small Molecules

Ligands 1 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
EDO	C [auth AAA], D [auth AAA], E [auth AAA], F [auth BBB]	1,2-ETHANEDIOL C2 H6 O2 LYCAIKOWRPUZTN-UHFFFAOYSA-N

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 1.99 Å
• R-Value Free:  0.245 (Depositor), 0.251 (DCC) 
• R-Value Work:  0.199 (Depositor), 0.202 (DCC) 

Space Group: P 1 2₁ 1

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 30.508	α = 90
b = 97.867	β = 101.914
c = 38.626	γ = 90

Software Package:

Software Name	Purpose
SCALA	data scaling
REFMAC	refinement
PDB_EXTRACT	data extraction
iMOSFLM	data reduction
PHENIX	phasing

Structure Validation

Entry History 

& Funding Information

Deposition Data

• Released Date: 2024-04-17 
Deposition Author(s): Havlickova, P., Bartosova-Sojkova, P., Sojka, D., Kascakova, B., Gavira, J.A., Kuta Smatanova, I.

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Funding Organization	Location	Grant Number
Grant Agency of the Czech Republic	Czech Republic	21-16565S
European Regional Development Fund	European Union	CZ.02.1.01/0.0/0.0/15_003/0000441

Revision History  

• Version 1.0: 2024-04-17
  Type: Initial release
  
• Version 1.1: 2026-03-04
  Changes: Refinement description, Structure summary
• Version 1.2: 2026-06-03
  Changes: Database references