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Deciphering metal ion preference and primary coordination sphere robustness of a designed zinc finger with high‐resolution mass spectrometry
Author(s) -
Laitaoja Mikko,
Isoniemi Sari,
Valjakka Jarkko,
Mándity István M.,
Jänis Janne
Publication year - 2017
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1002/pro.3067
Subject(s) - chemistry , zinc , zinc finger , histidine , protein design , cysteine , metal ions in aqueous solution , metal , crystallography , amino acid , protein structure , biochemistry , enzyme , organic chemistry , transcription factor , gene
Small zinc finger (ZnF) motifs are promising molecular scaffolds for protein design owing to their structural robustness and versatility. Moreover, their characterization provides important insights into protein folding in general. ZnF motifs usually possess an exceptional specificity and high affinity towards Zn(II) ion to drive folding. While the Zn(II) ion is canonically coordinated by two cysteine and two histidine residues, many other coordination spheres also exist in small ZnFs, all having four amino acid ligands. Here we used high‐resolution mass spectrometry to study metal ion binding specificity and primary coordination sphere robustness of a designed zinc finger, named MM1. Based on the results, MM1 possesses high specificity for zinc with sub‐micromolar binding affinity. Surprisingly, MM1 retains metal ion binding affinity even in the presence of selective alanine mutations of the primary zinc coordinating amino acid residues.