Novel complex MAD phasing and RNase H structural insights using selenium oligonucleotides.
Acta Crystallogr D Biol Crystallogr
; 70(Pt 2): 354-61, 2014 Feb.
Article
en En
| MEDLINE
| ID: mdl-24531469
ABSTRACT
The crystal structures of protein-nucleic acid complexes are commonly determined using selenium-derivatized proteins via MAD or SAD phasing. Here, the first protein-nucleic acid complex structure determined using selenium-derivatized nucleic acids is reported. The RNase H-RNA/DNA complex is used as an example to demonstrate the proof of principle. The high-resolution crystal structure indicates that this selenium replacement results in a local subtle unwinding of the RNA/DNA substrate duplex, thereby shifting the RNA scissile phosphate closer to the transition state of the enzyme-catalyzed reaction. It was also observed that the scissile phosphate forms a hydrogen bond to the water nucleophile and helps to position the water molecule in the structure. Consistently, it was discovered that the substitution of a single O atom by a Se atom in a guide DNA sequence can largely accelerate RNase H catalysis. These structural and catalytic studies shed new light on the guide-dependent RNA cleavage.
Palabras clave
Texto completo:
1
Banco de datos:
MEDLINE
Asunto principal:
Oligonucleótidos
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Selenio
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Proteínas Bacterianas
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ADN de Cadena Simple
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ARN
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Ribonucleasa H
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Escherichia coli
Idioma:
En
Año:
2014
Tipo del documento:
Article