Competitive Dissociation Reactions of Ternary Complexes Containing Ni(II), Nitrilotriacetic Acid and Alternative Metal Binding Peptides

Author

Perfect Asare

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Chemistry

Date of Award

1-10-2024

Abstract

Immobilized-metal affinity chromatography (IMAC) is a common technique used to purify recombinant proteins based on the affinity between a peptide tag attached to the end of the protein and Ni(II). The affinity tag is commonly used in this technique although in some cases the tag can affect the protein’s activity. To identify alternative metal binding (amb5) peptide tags for IMAC purification, an energy-resolved threshold collision-induced dissociation (TCID) method was employed to study a series of negatively-charged [amb5+Ni(II)+NTA]- ternary complexes. These complexes competitively will dissociate to generate [amb5+Ni(II)]- + NTA or [NTA+Ni(II)]- + amb5, where NTA is nitrilotriacetic acid. The study includes four amb tags with the fundamental structures acetyl-Aa1-Aa2-Gly3-Pro4-Aa5-Gly6-Cys7, where the amino acids Aa1 is either Asp or His, Aa2 is either His or Cys and Aa5 is either Tyr or Gly. The TCID was conducted using an instrument that combines electrospray – ion mobility – mass spectrometry to determine the reaction cross sections and the thermochemistry of the reactions.

Advisor

Laurence Angel

Subject Categories

Chemistry | Physical Sciences and Mathematics

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