Abstract
The oxidation of the tryptophan residues of rye seed chitinase-a (RSC-a) and its isolated catalytic (Cat) domain by N-bromosuccinimide (NBS) was investigated in the absence and presence of oligomers of N-acetylglucosamine (GlcNAc)n. Based on the reactivity toward NBS at pH 5.9, the seven tryptophan residues present in RSC-a are grouped into highly reactive (HR-), low reactive (LR-), and unreactive residues. Analyses of the peptides from 1 tryptophan- and 3 tryptophan-oxidized RSC-a showed that the HR-residue is Trp23 and the LR-residues are Trp131 and Trp141. The chitin-binding ability of RSC-a was lost upon the NBS oxidation of Trp23 at pH 5.9 or pH 7.0. This oxidation was prevented by (GlcNAc)3, which induced a high UV-difference spectrum with maxima at 284 and 293 nm. On the other hand, the chitinase activity of the Cat domain was greatly reduced by the NBS oxidation of Trp131 and Trp141 at pH 5.9, while in the NBS oxidation at pH 6.4, approximately one tryptophan residue was oxidized and about half of the activity was retained. The NBS oxidation of the isolated Cat domain at pH 5.9 was protected by (GlcNAc)4, which induced a UV-difference spectrum with maxima at 284 nm and 293 nm as well as a small trough around 300 nm, similar to that observed in RSC-c. From these results and the previous result that Trp72 in RSC-c is involved in the substrate-binding, it was suggested that Trp23 is highly exposed on the surface of the RSC-a molecule and involved in the chitin-binding, while Trp131 is involved in substrate-binding in its enzyme action.
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Claims 13
Claim · model-written summary
At pH 5.9, the seven tryptophans of rye seed chitinase-a fall into highly reactive, low reactive and unreactive classes by NBS reactivity.
- Taxon
- Rye
Secale cerealet0 - Gene
- Rye Seed Chitinase-at0
- Outcome
- reactivity toward NBSe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Rye Seed Chitinase-a”
e0“Based on the reactivity toward NBS at pH 5.9, the seven tryptophan residues present in RSC-a are grouped into highly reactive (HR-), low reactive (LR-), and unreactive residues”
Claim · model-written summary
Trp23 is the highly reactive residue of rye seed chitinase-a.
- Taxon
- RyeSecale cerealet0
- Gene
- Rye Seed Chitinase-at0
- Outcome
- HR-residuee1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Rye Seed Chitinase-a”
e1“the HR-residue is Trp23 and the LR-residues are Trp131 and Trp141”
Claim · model-written summary
Trp131 and Trp141 are the low reactive residues of rye seed chitinase-a.
- Taxon
- RyeSecale cerealet0
- Gene
- Rye Seed Chitinase-at0
- Outcome
- LR-residuese1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Rye Seed Chitinase-a”
e1“the HR-residue is Trp23 and the LR-residues are Trp131 and Trp141”
Claim · model-written summary
NBS oxidation of Trp23 at pH 5.9 or pH 7.0 abolished the chitin-binding ability of rye seed chitinase-a.
- Taxon
- RyeSecale cerealet0
- Treatment
- NBS oxidation of Trp23e2
- Gene
- Rye Seed Chitinase-at0
- Outcome
- chitin-binding abilitye2
- Direction
- loste2
- Qualifier
- at pH 5.9 or pH 7.0e2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Rye Seed Chitinase-a”
e2“The chitin-binding ability of RSC-a was lost upon the NBS oxidation of Trp23 at pH 5.9 or pH 7.0”
Claim · model-written summary
(GlcNAc)3 prevented the NBS oxidation of Trp23 in rye seed chitinase-a.
- Taxon
- RyeSecale cerealet0
- Treatment
- (GlcNAc)3e3
- Outcome
- oxidatione3
- Direction
- preventede3
- Qualifier
- NBS oxidation of Trp23e2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Rye Seed Chitinase-a”
e2“The chitin-binding ability of RSC-a was lost upon the NBS oxidation of Trp23 at pH 5.9 or pH 7.0”
e3“This oxidation was prevented by (GlcNAc)3, which induced a high UV-difference spectrum with maxima at 284 and 293 nm”
Claim · model-written summary
NBS oxidation of the isolated Cat domain at pH 5.9 was protected by (GlcNAc)4.
- Taxon
- RyeSecale cerealet0
- Treatment
- (GlcNAc)4e6
- Gene
- Cat domaine6
- Outcome
- NBS oxidation of the isolated Cat domaine6
- Direction
- protectede6
- Qualifier
- at pH 5.9e6
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Rye Seed Chitinase-a”
e6“The NBS oxidation of the isolated Cat domain at pH 5.9 was protected by (GlcNAc)4, which induced a UV-difference spectrum with maxima at 284 nm and 293 nm as well as a small trough around 300 nm, similar to that observed in RSC-c”
Claim · model-written summary
NBS oxidation of Trp131 and Trp141 at pH 5.9 greatly reduced the chitinase activity of the Cat domain.
- Taxon
- RyeSecale cerealet0
- Treatment
- NBS oxidation of Trp131 and Trp141e4
- Gene
- Cat domaine4
- Outcome
- chitinase activity of the Cat domaine4
- Direction
- greatly reducede4
- Qualifier
- at pH 5.9e4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Rye Seed Chitinase-a”
e4“the chitinase activity of the Cat domain was greatly reduced by the NBS oxidation of Trp131 and Trp141 at pH 5.9”
Claim · model-written summary
At pH 6.4, NBS oxidation oxidized approximately one tryptophan residue of rye seed chitinase-a.
- Taxon
- RyeSecale cerealet0
- Treatment
- NBS oxidatione5
- Outcome
- tryptophan residuee5
- Value
- approximately onee5
- Qualifier
- at pH 6.4e5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Rye Seed Chitinase-a”
e5“in the NBS oxidation at pH 6.4, approximately one tryptophan residue was oxidized and about half of the activity was retained”
Claim · model-written summary
At pH 6.4, NBS oxidation left about half of the chitinase activity retained.
- Taxon
- RyeSecale cerealet0
- Treatment
- NBS oxidatione5
- Outcome
- activitye5
- Direction
- retainede5
- Value
- about halfe5
- Qualifier
- at pH 6.4e5
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Rye Seed Chitinase-a”
e5“in the NBS oxidation at pH 6.4, approximately one tryptophan residue was oxidized and about half of the activity was retained”
Claim · model-written summary
(GlcNAc)3 induced a UV-difference spectrum of rye seed chitinase-a with maxima at 284 and 293 nm.
- Taxon
- RyeSecale cerealet0
- Treatment
- (GlcNAc)3e3
- Outcome
- UV-difference spectrume3
- Value
- 284 and 293 nme3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Rye Seed Chitinase-a”
e3“This oxidation was prevented by (GlcNAc)3, which induced a high UV-difference spectrum with maxima at 284 and 293 nm”
Claim · model-written summary
(GlcNAc)4 induced a UV-difference spectrum with maxima at 284 nm and 293 nm, similar to that of RSC-c.
- Taxon
- RyeSecale cerealet0
- Treatment
- (GlcNAc)4e6
- Outcome
- UV-difference spectrume6
- Value
- 284 nm and 293 nme6
- Comparator
- RSC-ce6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Rye Seed Chitinase-a”
e6“The NBS oxidation of the isolated Cat domain at pH 5.9 was protected by (GlcNAc)4, which induced a UV-difference spectrum with maxima at 284 nm and 293 nm as well as a small trough around 300 nm, similar to that observed in RSC-c”
Claim · model-written summary
Trp23 is probably highly exposed on the surface of the RSC-a molecule and involved in chitin binding.
- Taxon
- RyeSecale cerealet0
- Gene
- Rye Seed Chitinase-at0
- Outcome
- chitin-bindinge7
- Qualifier
- Trp23 is highly exposed on the surface of the RSC-a moleculee7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Rye Seed Chitinase-a”
e7“Trp23 is highly exposed on the surface of the RSC-a molecule and involved in the chitin-binding, while Trp131 is involved in substrate-binding in its enzyme action”
Claim · model-written summary
Trp131 is probably involved in substrate binding during the enzyme action of rye seed chitinase-a.
- Taxon
- RyeSecale cerealet0
- Gene
- Rye Seed Chitinase-at0
- Outcome
- substrate-bindinge7
- Qualifier
- Trp131 is involved in substrate-binding in its enzyme actione7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Rye Seed Chitinase-a”
e7“Trp23 is highly exposed on the surface of the RSC-a molecule and involved in the chitin-binding, while Trp131 is involved in substrate-binding in its enzyme action”