Crystal structure of the human MBL-associated protein 19 (MAp19)

Experimental Data Snapshot

  • Resolution: 2.50 Å
  • R-Value Free: 0.316 
  • R-Value Work: 0.261 
  • R-Value Observed: 0.263 

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The X-ray structure of human MBL-associated protein 19 (MAp19) and its interaction site with mannan-binding lectin and L-ficolin

Gregory, L.A.Thielens, N.M.Matsushita, M.Sorensen, R.Arlaud, G.J.Fontecilla-Camps, J.C.Gaboriaud, C.

(2004) J Biol Chem 279: 29391-29397

  • DOI: https://doi.org/10.1074/jbc.M402687200
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    MAp19 is an alternative splicing product of the MASP-2 gene comprising the N-terminal CUB1-epidermal growth factor (EGF) segment of MASP-2, plus four additional residues at its C-terminal end. Like full-length MASP-2, it forms Ca(2+)-dependent complexes with mannan-binding lectin (MBL) and L-ficolin. The x-ray structure of human MAp19 was solved to a resolution of 2.5 A. It shows a head to tail homodimer held together by interactions between the CUB1 module of one monomer and the EGF module of its counterpart. A Ca(2+) ion bound to each EGF module stabilizes the dimer interfaces. A second Ca(2+) ion is bound to the distal end of each CUB1 module, through six ligands contributed by Glu(52), Asp(60), Asp(105), Ser(107), Asn(108), and a water molecule. Compared with its counterpart in human C1s, the N-terminal end of the MAp19 CUB1 module contains a 7-residue extension that forms additional inter-monomer contacts. To identify the residues involved in the interaction of MAp19 with MBL and L-ficolin, point mutants were generated and their binding ability was determined using surface plasmon resonance spectroscopy. Six mutations at Tyr(59), Asp(60), Glu(83), Asp(105), Tyr(106), and Glu(109) either strongly decreased or abolished interaction with both MBL and L-ficolin. These mutations map a common binding site for these proteins located at the distal end of each CUB1 module and stabilized by the Ca(2+) ion.

  • Organizational Affiliation

    Laboratoire de Cristallographie et Cristallogénèse des Protéines, France.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
mannose binding lectin-associated serine protease-2 related protein, MAp19 (19kDa)
A, B
170Homo sapiensMutation(s): 0 
Gene Names: MASP2
UniProt & NIH Common Fund Data Resources
Find proteins for O00187 (Homo sapiens)
Explore O00187 
Go to UniProtKB:  O00187
PHAROS:  O00187
GTEx:  ENSG00000009724 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupO00187
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.50 Å
  • R-Value Free: 0.316 
  • R-Value Work: 0.261 
  • R-Value Observed: 0.263 
  • Space Group: P 43 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 67.754α = 90
b = 67.754β = 90
c = 187.923γ = 90
Software Package:
Software NamePurpose
XDSdata scaling
XDSdata reduction

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2004-06-22
    Type: Initial release
  • Version 1.1: 2008-04-30
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2023-08-23
    Changes: Data collection, Database references, Derived calculations, Refinement description