4NOS:
reference: Structural characterization of nitric oxide synthase isoforms reveals striking active-site conservation., Fischmann TO, Hruza A, Niu XD, Fossetta JD, Lunn CA, Dolphin E, Prongay AJ, Reichert P, Lundell DJ, Narula SK, Weber PC, Nat Struct Biol 1999 Mar;6(3):233-42. PMID: 10074942

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