Collision Cross Section Determination of Lysozyme and Methanobactin Analog Peptide by Travelling Wave Ion Mobility Mass Spectrometry

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Chemistry

Date of Award

Fall 2013

Abstract

The research presented here developed techniques for calculating the collision cross-sections of various charged species of native and disulfide reduced lysozyme treated with 50-fold molar excess of Zn2+. The measurements were compared to the collision cross-sections calculated from previously published lysozyme conformations from X-ray crystallography and nuclear magnetic resonance spectroscopy and were found to be in good agreement with these structures. The technique was then extended to measuring the collision cross-sections of methanobactin complexes. Methanobactin is a copper binding and reducing chromophoric peptide initially identified in Methylosinus trichosporium OB3b (mb-Ob3b). Previous ion mobility mass spectrometry results show mb-OB3b exists in the gas-phase as three different negatively-charged states and in multiple conformational states, depending on its charge state and whether it is bound to Cu(I), when introduced via electrospray ionization from aqueous solution near physiological pH. The aim of the research is to convert the mb-OB3b analog peptide (ac-HCGPHC) drift time measurements into collision cross sections (Å2) using our developed calibration procedure utilizing α, ω - dicarboxy polystyrene calibrants in order to determine the relative conformations of the various negative charged species of ac-HCGPHC and tetra-glycine, penta-glycine and Angiotensin (I and II) are utilized as calibrants in case of positive charged species of ac-HCGPHC.

Advisor

Laurence Angel

Subject Categories

Chemistry | Physical Sciences and Mathematics

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