Solution structure and DNA-binding properties of a thermostable protein from the archaeon Sulfolobus solfataricus.
The archaeon Sulfolobus solfataricus expresses large amounts of a small basic protein, Sso7d, which was previously identified as a DNA-binding protein possibly involved in compaction of DNA. We have determined the solution structure of Sso7d. The protein consists of a triple-stranded anti-parallel beta-sheet onto which an orthogonal double-stranded beta-sheet is packed. This topology is very similar to that found in eukaryotic Src homology-3 (SH3) domains. Sso7d binds strongly (Kd < 10 microM) to double-stranded DNA and protects it from thermal denaturation. In addition, we note that epsilon-mono-methylation of lysine side chains of Sso7d is governed by cell growth temperatures, suggesting that methylation is related to the heat-shock response.
Baumann
H
H
Center for Structural Biochemistry, Karolinska Institutet, NOVUM, Huddinge, Sweden.
Knapp
S
S
Lundbäck
T
T
Ladenstein
R
R
Härd
T
T
D000595:Amino Acid Sequence; D019843:Archaeal Proteins; D001426:Bacterial Proteins / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D006358:Hot Temperature; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D009691:Nucleic Acid Denaturation; D011485:Protein Binding; D011487:Protein Conformation; D017386:Sequence Homology, Amino Acid; D012996:Solutions; D016944:Sulfolobus / Q000737:chemistry*
D019843:Archaeal Proteins; D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D012996:Solutions; C093228:Sso7d protein, Sulfolobus; D004247:DNA