Open AccessConformation of Methylated Sequences in HeLa Cell 18‐S Ribosomal RNA: Nuclease S 1 as a Probe
Author(s) -
KHAN M. Shah N.,
MADEN B. Edward H.
Publication year - 1978
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1978.tb12162.x
Subject(s) - nuclease , ribosome , ribonuclease , hela , ribosomal rna , rna , nucleotide , rnase p , biochemistry , digestion (alchemy) , pancreatic ribonuclease , chemistry , microbiology and biotechnology , micrococcal nuclease , biology , enzyme , dna , cell , chromatography , nucleosome , histone , gene
18‐S rRNA from HeLa cells was digested with nuclease S 1 . Under the conditions employed 15% of the total nucleotides and some 50% of the methylated nucleotides were released as low‐molecular‐weight products. The material which was precipitable by 70% ethanol after nuclease S 1 digestion was subjected to further digestion by combined T 1 plus pancreatic riboncleases or by T 1 ribonuclease alone, and fingerprints were prepared. It was found that the four sites which are modified late during ribosome maturation, and which contain base modifications, were all accessible to nuclease S 1 . By contrast fewer than one‐half of the sites which are modified early during ribosome maturation, and which contain 2′‐ O ‐methyl groups, were accessible to nuclease S 1 ; the remainder were protected, presumably by secondary or tertiary interactions within 18‐S rRNA.