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Expression, purification and crystallization of a protein resulting from the inversion of the amino‐acid sequence of a helical bundle
Author(s) -
Kefala Aikaterini,
Kotsifaki Dina,
Providaki Mary,
Amprazi Maria,
Kokkinidis Michael
Publication year - 2017
Publication title -
acta crystallographica section f
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.572
H-Index - 37
ISSN - 2053-230X
DOI - 10.1107/s2053230x16020173
Subject(s) - crystallization , bundle , sequence (biology) , inversion (geology) , peptide sequence , crystallography , materials science , chemistry , biology , biochemistry , paleontology , composite material , organic chemistry , gene , structural basin
Earlier studies have found that the occurrence of inverse sequence identity in proteins is not indicative of three‐dimensional similarity, but rather leads to different folds or unfolded proteins. Short helices, however, frequently keep their conformations when their sequences are inverted. To explore the impact of sequence inversion on long helices, revRM6, with the inverse amino‐acid sequence relative to RM6, a highly stable variant of the ColE1 Rop protein, was engineered. RM6 is a highly regular four‐α‐helical bundle that serves as a model system for protein‐folding studies. Here, the crystallization and preliminary crystallographic characterization of revRM6 are reported. The protein was overexpressed in Escherichia coli , purified to homogeneity and crystallized. The crystals belonged to space group P 4 1 2 1 2, with unit‐cell parameters a = b = 44.98, c = 159.74 Å, and diffracted to a resolution of 3.45 Å.