Biochemical and structural characterization of Cren7, a novel chromatin protein conserved among Crenarchaea.
Archaea contain a variety of chromatin proteins consistent with the evolution of different genome packaging mechanisms. Among the two main kingdoms in the Archaea, Euryarchaeota synthesize histone homologs, whereas Crenarchaeota have not been shown to possess a chromatin protein conserved at the kingdom level. We report the identification of Cren7, a novel family of chromatin proteins highly conserved in the Crenarchaeota. A small, basic, methylated and abundant protein, Cren7 displays a higher affinity for double-stranded DNA than for single-stranded DNA, constrains negative DNA supercoils and is associated with genomic DNA in vivo. The solution structure and DNA-binding surface of Cren7 from the hyperthermophilic crenarchaeon Sulfolobus solfataricus were determined by NMR. The protein adopts an SH3-like fold. It interacts with duplex DNA through a beta-sheet and a long flexible loop, presumably resulting in DNA distortions through intercalation of conserved hydrophobic residues into the DNA structure. These data suggest that the crenarchaeal kingdom in the Archaea shares a common strategy in chromatin organization.
Guo
Li
L
State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, 3A Datun Road, Beijing 100101, PR China.
Feng
Yingang
Y
Zhang
Zhenfeng
Z
Yao
Hongwei
H
Luo
Yuanming
Y
Wang
Jinfeng
J
Huang
Li
L
D000595:Amino Acid Sequence; D019843:Archaeal Proteins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification; D002843:Chromatin / Q000737:chemistry*; D002868:Chromosomal Proteins, Non-Histone / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification; D017124:Conserved Sequence; D019615:Crenarchaeota / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification; D008958:Models, Molecular; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D016415:Sequence Alignment; D048229:Sulfolobus solfataricus / Q000235:genetics
D019843:Archaeal Proteins; D002843:Chromatin; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins