Crystal Structure of Archaeal Chromatin Protein Alba2-Double-stranded DNA Complex from Aeropyrum pernix K1

All thermophilic and hyperthermophilic archaea encode homologs of dimeric Alba (Sac10b) proteins that bind cooperatively at high density to DNA. Here, we report the 2.0 Å resolution crystal structure of an Alba2 (Ape10b2)-dsDNA complex from Aeropyrum pernix K1. A rectangular tube-like structure enco...

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Bibliographic Details
Published in:The Journal of biological chemistry 2012-03, Vol.287 (13), p.10394-10402
Main Authors: Tanaka, Tomoyuki, Padavattan, Sivaraman, Kumarevel, Thirumananseri
Format: Article
Language:English
Subjects:
Aeropyrum - chemistry
Aeropyrum - genetics
Aeropyrum - metabolism
Alba
Ape1823
Archaea
Archaeal Chromatin
Archaeal Proteins - chemistry
Archaeal Proteins - genetics
Archaeal Proteins - metabolism
Chromatin
Crystallography, X-Ray
DNA and Chromosomes
DNA, Archaeal - chemistry
DNA, Archaeal - genetics
DNA, Archaeal - metabolism
DNA-binding Protein
DNA-Binding Proteins - chemistry
DNA-Binding Proteins - genetics
DNA-Binding Proteins - metabolism
Nucleic Acid Structure
Protein Structure, Secondary
Protein Structure, Tertiary
Sso10b
Structural Biology
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Summary:All thermophilic and hyperthermophilic archaea encode homologs of dimeric Alba (Sac10b) proteins that bind cooperatively at high density to DNA. Here, we report the 2.0 Å resolution crystal structure of an Alba2 (Ape10b2)-dsDNA complex from Aeropyrum pernix K1. A rectangular tube-like structure encompassing duplex DNA reveals the positively charged residues in the monomer-monomer interface of each dimer packing on either side of the bound dsDNA in successive minor grooves. The extended hairpin loop connecting strands β3 and β4 undergoes significant conformational changes upon DNA binding to accommodate the other Alba2 dimer during oligomerization. Mutational analysis of key interacting residues confirmed the specificity of Alba2-dsDNA interactions. Alba is a dimeric, highly basic archaeal chromatin protein. The crystal structure of the Alba2-dsDNA complex was determined. Upon dsDNA binding, Alba undergoes a significant conformational change that is required for oligomerization. This study provides the first structural insights into how the Alba dimer binds and packs the dsDNA.
ISSN:0021-9258
1083-351X
DOI:10.1074/jbc.M112.343210