1IQQ:
reference: Crystal structure at 1.5-A resolution of Pyrus pyrifolia pistil ribonuclease responsible for gametophytic self-incompatibility., Matsuura T, Sakai H, Unno M, Ida K, Sato M, Sakiyama F, Norioka S, J Biol Chem 2001 Nov 30;276(48):45261-9. PMID: 11577107

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