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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
22
pubmed:dateCreated
2004-6-1
pubmed:abstractText
Barnase, a well-characterized ribonuclease, has been decomposed into six modules (M1-M6) or secondary structure units (S1-S6). We have studied the foldability and activity of the barnase mutants obtained by permutation of the four internal modules (M2-M5) or secondary structure units (S2-S5) to investigate whether permutation of these building blocks is a useful way to create foldable and/or functional proteins. In this study, we found that one of the secondary structure unit mutants was expressed in Escherichia coli only when His102 was substituted by alanine, which is a catalytic residue of wild-type barnase. This mutant (S2354H102A) had ordered conformations, which unfolded cooperatively during urea-induced unfolding experiments. S2354H102A interacted with other barnase mutants to show a distinct RNase activity, although its own activity was quite weak. This interaction was specific, because S2354H102A interacted with only barnase mutants having His 102 and certain orders of the secondary structure units giving a distinct RNase activity. These results suggest that secondary structure units permuted in barnase mutants maintain their intrinsic "interacting ability" that is used for the folding of wild-type barnase, and the units can form certain conformations that complement those of the appropriate counterparts. Seven of 23 secondary structure unit mutants and only 2 of 23 module mutants had RNase activity. On the basis of the results of analyses of foldability and RNase activity of the mutants performed in this and previous studies, we conclude that secondary structure units are more suitable than modules as building blocks to create novel foldable and/or functional proteins in the case of barnase.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
8
pubmed:volume
43
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
6968-75
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2004
pubmed:articleTitle
Foldability, enzymatic activity, and interacting ability of barnase mutants obtained by permutation of secondary structure units.
pubmed:affiliation
Department of Biosciences and Informatics, Faculty of Science and Technology, Keio University, 3-14-1, Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan.
pubmed:publicationType
Journal Article, Comparative Study