3B9I:
reference: Evolution of GITRL immune function: murine GITRL exhibits unique structural and biochemical properties within the TNF superfamily., Chattopadhyay K, Ramagopal UA, Brenowitz M, Nathenson SG, Almo SC, Proc Natl Acad Sci U S A. 2008 Jan 15;105(2):635-40. Epub 2008 Jan 8. PMID: 18182486

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