4TYN

DEAD-box helicase Mss116 bound to ssDNA and ADP-BeF

Summary for 4TYN

• Entry DOI: 10.2210/pdb4tyn/pdb
• Related: 4TYW 4TYY 4TZ0 4TZ6
• Descriptor: DNA (5'-D(P*AP*AP*AP*AP*AP*AP*A)-3'), ATP-dependent RNA helicase MSS116, mitochondrial, MAGNESIUM ION, ... (5 entities in total)
• Functional Keywords: dead-box, rna helicase, hydrolase, rna binding protein-dna complex, hydrolase-dna complex, hydrolase/dna
• Biological source: Saccharomyces cerevisiae (Baker's yeast); More
• Cellular location: Mitochondrion matrix : P15424
• Total number of polymer chains: 2
• Total formula weight: 60508.73

Authors

Mallam, A.L.,Sidote, D.J.,Lambowitz, A.M. (deposition date: 2014-07-08, release date: 2014-12-31, Last modification date: 2023-09-27)

Primary citation

Mallam, A.L.,Sidote, D.J.,Lambowitz, A.M.
Molecular insights into RNA and DNA helicase evolution from the determinants of specificity for a DEAD-box RNA helicase.
Elife, 3:e04630-e04630, 2014

PubMed Abstract: How different helicase families with a conserved catalytic 'helicase core' evolved to function on varied RNA and DNA substrates by diverse mechanisms remains unclear. In this study, we used Mss116, a yeast DEAD-box protein that utilizes ATP to locally unwind dsRNA, to investigate helicase specificity and mechanism. Our results define the molecular basis for the substrate specificity of a DEAD-box protein. Additionally, they show that Mss116 has ambiguous substrate-binding properties and interacts with all four NTPs and both RNA and DNA. The efficiency of unwinding correlates with the stability of the 'closed-state' helicase core, a complex with nucleotide and nucleic acid that forms as duplexes are unwound. Crystal structures reveal that core stability is modulated by family-specific interactions that favor certain substrates. This suggests how present-day helicases diversified from an ancestral core with broad specificity by retaining core closure as a common catalytic mechanism while optimizing substrate-binding interactions for different cellular functions.

PubMed: 25497230
DOI: 10.7554/eLife.04630

Experimental method

X-RAY DIFFRACTION (2.959 Å)