MJ1647, an open reading frame in the genome of the hyperthermophile Methanococcus jannaschii, encodes a very thermostable archaeal histone with a C-terminal extension |
| |
Authors: | Wen-Tyng Li Kathleen Sandman Suzette L Pereira John N Reeve |
| |
Institution: | (1) Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA Tel. +1-614-292-2301; Fax +1-614-292-8120 e-mail: reeve.2@osu.edu, US |
| |
Abstract: | All archaeal histones studied to date have similar lengths, 66 to 69 amino acid residues that form three α-helices separated
by two β-strand loop regions which together constitute a histone fold. In contrast, the eukaryal nucleosome core histones
are larger, 102 to 135 residues in length, with N-terminal and C-terminal extensions flanking the histone fold that participate
in gene regulation and higher-order chromatin assembly. In the Methanococcus jannaschii genome, MJ1647 was annotated as an open reading frame predicted to encode an archaeal histone with an approximately 27-amino-acid
C-terminal extension, and we here document the DNA binding and assembly properties and thermodynamic stability parameters
of the recombinant product of MJ1647 synthesized in Escherichia coli with (rMJ1647) and without (rMJ1647Δ) the C-terminal extension. The presence of the C-terminal extension did not prevent
homodimer formation or inhibit DNA binding, but the complexes formed by rMJ1647, presumably archaeal nucleosomes containing
a (rMJ1647)4 tetramer, were apparently less stable than those formed by (rMJ1647Δ)4. The presence of the C-terminal extension increased the thermostability of rMJ1647 when compared with rMJ1647Δ in 0.2 M KCl
at pH 4 but not in the absence of KCl at pH 1. Based on thermal unfolding transitions, rMJ1647 and rHAfB generated by expression
of AF0337 cloned from the genome of the related hyperthermophile Archaeoglobus fulgidus in E. coli were found to have higher thermodynamic stabilities than all previously studied archaeal histones.
Received: September 2, 1999 / Accepted: October 18, 1999 |
| |
Keywords: | Histone fold Recombinant protein Thermostability DNA packaging Archaeoglobus fulgidus Circular dichroism |
本文献已被 PubMed SpringerLink 等数据库收录! |
|