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Binding of PDZ domains to the carboxy terminus of inducible nitric oxide synthase boosts electron transfer and NO synthesis
Author(s) -
Aicart-Ramos Clara,
Rodríguez-Crespo Ignacio
Publication year - 2015
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2015.07.004
Subject(s) - pdz domain , chemistry , biochemistry , nitric oxide synthase , electron transfer , enzyme , atp synthase , n terminus , biophysics , microbiology and biotechnology , stereochemistry , biology , peptide sequence , gene , organic chemistry
iNOS lacks any phosphorylatable residue at its C‐terminus despite displaying a 25‐residue extension known to block electron transfer and activity. We report that C‐terminal deletions of iNOS increased the cytochrome c reduction rate. Moreover, the interaction of the iNOS C‐terminus with the PDZ domains of EBP50 or CAP70 resulted not only in augmented reductase activity and greater NO synthesis but also anticipated the formation of the air‐stable semiquinone generated after NADPH addition. Hence, the C‐terminus of iNOS regulates the activity of the enzyme, albeit, unlike nNOS and eNOS, displacement of the autoinhibitory element occurs upon binding to proteins with PDZ domains.