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. Author manuscript; available in PMC: 2013 Dec 1.
Published in final edited form as: Arch Biochem Biophys. 2012 Sep 11;528(1):72–89. doi: 10.1016/j.abb.2012.09.002

Figure 12.

Figure 12

The structure of the iNOS CaM·FMN complex and interactions between the FMN domain and the bound CaM. The FMN domain is shown in gold, CaM in green, and Ca2+ with grey balls. The CaM binding region is shown with a gold helix wrapped around by green CaM. FMN is shown with blue sticks. Arg536 located within the hinge between the FMN domain and the CaM binding region makes salt bridges and a hydrogen bond with Glu47 and Asn42 of CaM, respectively. Arg536 also makes several hydrogen bonds with the main chain carbonyl oxygens of Ser562-Cys563-Ala564-Phe565 of the FMN domain. Thus, the Ca2+-CaM binding regulates the hinge motion pivoting at Arg563, which in turn controls ET from FAD to FMN and from FMN to heme.