Abstract
The thermostability of potato type L alpha-glucan phosphorylase (EC 2.4.1.1) was enhanced by random and site-directed mutagenesis. We obtained three single-residue mutations-Phe39-->Leu (F39L), Asn135-->Ser (N135S), and Thr706-->Ile (T706I)-by random mutagenesis. Although the wild-type enzyme was completely inactivated, these mutant enzymes retained their activity even after heat treatment at 60 degrees C for 2 h. Combinations of these mutations were introduced by site-directed mutagenesis. The simultaneous mutation of two (F39L/N135S, F39L/T706I, and N135S/T706I) or three (F39L/N135S/T706I) residues further increased the thermostability of the enzyme, indicating that the effect of the replacement of the residues was cumulative. The triple-mutant enzyme, F39L/N135S/T706I, retained 50% of its original activity after heat treatment at 65 degrees C for 20 min. Further analysis indicated that enzymes with a F39L or T706I mutation were resistant to possible proteolytic degradation.
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Claims 5
Claim · model-written summary
Three single residue mutations were obtained by random mutagenesis.
- Taxon
- potato
Solanum tuberosume1 - Gene
- Phe39-->Leu (F39L), Asn135-->Ser (N135S), and Thr706-->Ile (T706I)e0
- Outcome
- three single-residue mutationse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“We obtained three single-residue mutations-Phe39-->Leu (F39L), Asn135-->Ser (N135S), and Thr706-->Ile (T706I)-by random mutagenesis”
e1“potato type L alpha-glucan phosphorylase”
Claim · model-written summary
Single mutation enzymes retained activity after 60 degrees C for two hours, whereas wild type was inactivated.
- Taxon
- potatoSolanum tuberosume1
- Treatment
- heat treatment at 60 degrees C for 2 he0
- Gene
- mutant enzymese0
- Outcome
- retained their activitye0
- Comparator
- wild-type enzymee0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Although the wild-type enzyme was completely inactivated, these mutant enzymes retained their activity even after heat treatment at 60 degrees C for 2 h”
e1“potato type L alpha-glucan phosphorylase”
Claim · model-written summary
Double and triple substitutions further increased enzyme thermostability.
- Taxon
- potatoSolanum tuberosume1
- Treatment
- simultaneous mutation of two (F39L/N135S, F39L/T706I, and N135S/T706I) or three (F39L/N135S/T706I) residuese0
- Outcome
- thermostability of the enzymee0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The simultaneous mutation of two (F39L/N135S, F39L/T706I, and N135S/T706I) or three (F39L/N135S/T706I) residues further increased the thermostability of the enzyme”
e1“potato type L alpha-glucan phosphorylase”
Claim · model-written summary
The triple mutant retained 50% of its activity after heat treatment at 65 degrees C for 20 min.
- Taxon
- potatoSolanum tuberosume1
- Treatment
- heat treatment at 65 degrees C for 20 mine0
- Gene
- F39L/N135S/T706Ie0
- Outcome
- original activitye0
- Value
- 50%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The triple-mutant enzyme, F39L/N135S/T706I, retained 50% of its original activity after heat treatment at 65 degrees C for 20 min”
e1“potato type L alpha-glucan phosphorylase”
Claim · model-written summary
Enzymes carrying F39L or T706I resisted possible proteolytic degradation.
- Taxon
- potatoSolanum tuberosume1
- Gene
- F39L or T706Ie0
- Outcome
- resistant to possible proteolytic degradatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“enzymes with a F39L or T706I mutation were resistant to possible proteolytic degradation”
e1“potato type L alpha-glucan phosphorylase”
The same questions in other papers
loss of function · physiology: enzyme activity · Solanum tuberosum (potato)Results agree
3 papers in the same direction as this paper
- positive
- positive
- positive
Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.