1ZLE

Crystal structure of a RGD-containing host-selective toxin: Pyrenophora tritici-repentis Ptr ToxA

Summary for 1ZLE

• Entry DOI: 10.2210/pdb1zle/pdb
• Related: 1ZLD
• Descriptor: Ptr necrosis toxin, NICKEL (II) ION (3 entities in total)
• Functional Keywords: beta-sandwich; rgd-motif, toxin
• Biological source: Pyrenophora tritici-repentis
• Total number of polymer chains: 3
• Total formula weight: 40092.81

Authors

Sarma, G.N.,Manning, V.A.,Ciuffetti, L.M.,Karplus, P.A. (deposition date: 2005-05-06, release date: 2005-08-16, Last modification date: 2024-10-30)

Primary citation

Sarma, G.N.,Manning, V.A.,Ciuffetti, L.M.,Karplus, P.A.
Structure of Ptr ToxA: An RGD-Containing Host-Selective Toxin from Pyrenophora tritici-repentis
Plant Cell, 17:3190-3202, 2005

PubMed Abstract: Tan spot of wheat (Triticum aestivum), caused by the fungus Pyrenophora tritici-repentis, has significant agricultural and economic impact. Ptr ToxA (ToxA), the first discovered proteinaceous host-selective toxin, is produced by certain P. tritici-repentis races and is necessary and sufficient to cause cell death in sensitive wheat cultivars. We present here the high-resolution crystal structure of ToxA in two different crystal forms, providing four independent views of the protein. ToxA adopts a single-domain, beta-sandwich fold of novel topology. Mapping of the existing mutation data onto the structure supports the hypothesized importance of an Arg-Gly-Asp (RGD) and surrounding sequence. Its occurrence in a single, solvent-exposed loop in the protein suggests that it is directly involved in recognition events required for ToxA action. Furthermore, the ToxA structure reveals a surprising similarity with the classic mammalian RGD-containing domain, the fibronectin type III (FnIII) domain: the two topologies are related by circular permutation. The similar topologies and the positional conservation of the RGD-containing loop raises the possibility that ToxA is distantly related to mammalian FnIII proteins and that to gain entry it binds to an integrin-like receptor in the plant host.

PubMed: 16214901
DOI: 10.1105/tpc.105.034918

Experimental method

X-RAY DIFFRACTION (1.9 Å)