Letter: Mass Spectrometric Evidence for Iron Binding to the Neuroprotective Peptide NAP and its Cys5 Mutant. Issue 2 (April 2016)

• Record Type: Journal Article
• Authors: Ciobanu, Catalina-Ionica; Stefanescu, Raluca; Niculaua, Marius; Teslaru, Teodora; Gradinaru, Robert; Drochioiu, Gabi
• Is Part Of: European journal of mass spectrometry. Volume 22:Issue 2(2015)
• Page Start: 97
• Page End: 104
• Publication Date: 2016-04
• Subjects: NAP peptide -- MALDI-ToF MS -- iron binding -- Alzheimer's disease; Mass spectrometry -- Periodicals; Mass Spectrometry; Mass spectrometry; Periodicals; Periodicals; 543.6505
• DOI: 10.1255/ejms.1414
• Languages: English
• ISSNs: 1469-0667

Abstract

The NAP peptide (H2 N- 1 NAPVSIPQ 8 -CONH2 ) is a truncated version of the activity-dependent neuroprotective protein. Its neuroprotective activities consist of the inhibition of Aβ(25–35) and Aβ(1–40) fibrillogenesis as well as protection against Aβ-induced neurotoxicity and prevention of microtubule disruption associated with Alzheimer's disease. Therefore, we synthesized NAP and its mutant peptide with the sequence H2 N- 1 NAPVCIPQ 8 -COOH (NAPCOH) by replacing serine S 5 with cysteine C 5 . Both native and mutant peptides were further used to study their interaction with iron ions. Matrix-assisted laser desorption/ionization-time of flight mass spectrometry, Fourier transform infrared spectroscopy and also atomic force microscopy were used to probe Fe 3 + binding to both peptides. Contrary to the expected results, the investigated peptides underwent different oxidation processes, with resultant reduced Fe 2 + ions. These ions, and not the original Fe 3 + ions, were found to bind to each of the non-oxidized peptides.