DOI: 10.7924/r4nv9q11m
title: Data from: Intramolecular histidine crosslinks formed via copper-catalyzed oxidation of histatin peptides

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DATA & FILE OVERVIEW
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NMR Data:
Raw NMR folder:
	HHGY - folder for raw NMR data for peptide HHGY
		Info.txt - Text file detailing NMR sample preparation, collection, and processing
		HHGY_structure.mol - Mole file drawing of chemical structure of peptide HHGY 	
		1H - folder for raw proton NMR experiment data including FID, processing parameters, and acquisition parameters
		1H-13C HMBC - folder for raw proton - carbon heteronuclear multiple bond correlation NMR experiment data including FID, processing parameters, and acquisition parameters
		13C - folder for raw carbon NMR experiment data including FID, processing parameters, and acquisition parameters	
	oxHHGY - folder for raw NMR data for peptide mixture oxHHGY
		Info.txt - Text file detailing NMR sample preparation, collection, and processing
		oxHHGY_structure.mol - Mole file drawing of chemical structure of peptide oxHHGY 	
		1H - folder for raw proton NMR experiment data including FID, processing parameters, and acquisition parameters
		1H-13C HMBC - folder for raw proton - carbon heteronuclear multiple bond correlation NMR experiment data including FID, processing parameters, and acquisition parameters
		13C - folder for raw carbon NMR experiment data including FID, processing parameters, and acquisition parameters

Mass spectrometry data:
MS1.csv - mass spectrometry ions and intensities of reaction mixture containing Native and oxidized Hist1-12 peptides, the following MS data files are collected by selecting ions in this MS1 file for tandem MS analysis
497.csv - tandem mass spectrometry of 497 ion, [M+3H]3+ of Native Hist1-12
503.csv - tandem mass spectrometry of 503 ion, [M+16+3H]3+ of Native Hist1-12, single oxygenation
508.csv - tandem mass spectrometry of 508 ion, [M+32+3H]3+ of Native Hist1-12, double oxygenation
513.csv - tandem mass spectrometry of 513 ion, [M+48+3H]3+ of Native Hist1-12, triple oxygenation
770.csv - tandem mass spectrometry of 770 ion, [M+48+2H]2+ of Native Hist1-12, triple oxygenation
497-xlink.csv - tandem mass spectrometry of 496 ion, [M-2+3H]3+ of Native Hist1-12, crosslink
746-xlink.csv - tandem mass spectrometry of 744 ion, [M-2+2H]2+ of Native Hist1-12, crosslink
513-xlink.csv - tandem mass spectrometry of 512 ion, [M+46+3H]3+ of Native Hist1-12, triple oxygenation and crosslink
770-xlink.csv - tandem mass spectrometry of 768 ion, [M+46+2H]2+ of Native Hist1-12, triple oxygenation and crosslink


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METHODOLOGICAL INFORMATION
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Description of methods used for collection/generation of data: 

NMR Sample Preparation, Collection, and Processing: Dried peptides were reconstituted with nanopure H2O and transferred to 3 mm tubes. A sealed capillary tube containing D2O with 1% trimethylsilane (TMS) was added to the sample. Spectra were collected on an Agilent/Varian DirectDrive2 800 MHz spectrometer at ambient temperature. The H2O signal was suppressed via a pre-saturation protocol. Spectra were acquired with Vnmr software and processed with Bruker TopSpin 4.1.1 software. Processing the data from Varian to TopSpin was accomplished according to this video: https://chembio.byu.edu/nmr-video-varian-topspin . Spectra were calibrated with TMS signal at 0 ppm.

Mass Spectrometry Sample Preparation, Collection, and Analysis: For peptide sequencing analysis, a solution of 1 mM Hist1-12, 0.9 mM Cu(II), 5 mM ascorbate and 5 mM H2O2 at a total volume of 500 µL was reacted for 60 min and monitored by UV/vis spectroscopy. The sample was injected onto a reverse-phase HPLC prep column, and the fraction with 390 nm signal was collected, rotovapped, and lyophilized. The lyophilized solid was initially dissolved in water, then diluted into 90:10 water:acetonitrile with 0.1% formic acid. This sample was diluted again either ten times or 100 times in 90:10 water:acetonitrile. The samples were analyzed on a Thermo Orbitrap Exploris 480 instrument. Analysis was conducted by direct infusion using a syringe pump. For sequencing crosslinked masses, MS2 window was selected to be very narrow (1.5 ppm or less) in an effort to exclude ions from the native peptide. Theoretical masses were calculated with Microsoft Excel version 2412. Observed masses were recorded from most intense mass nearest calculated ion. For peptides sequenced at multiple charge states, observed masses were recorded using ions from both charge states.					

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DATA-SPECIFIC INFORMATION 
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Abbreviations:
NMR - nuclear magnetic resonance
MS - mass spectrometry
HHGY - a peptide with sequence Histidine-Histidine-Glycine-Tyrosine
oxHHGY - the mixture of peptide products resulting from HHGY copper catalyzed oxidation 

For Mass Spectrometry data:

Variable/field list
Mass = mass to charge ratio (m/z) of an observed ion
Intensity = the height of the peak for the observed ion

Value/attribute list
Mass : given in units of Dalton
Charge : an integer from 1-4, indicating how many positive charges the observed ion has
Intensity : arbitrary units
   
Missing data treatments
Masses that were not observed are marked with '0'