Mouse acidic mammalian chitinase exhibits transglycosylation activity at somatic tissue pH

Wakita, Satoshi; Kobayashi, Shunsuke; Kimura, Masahiro; Kashimura, Akinori; Honda, Susumu; Sakaguchi, Minoru; Sugahara, Yoshiyuki; Kamaya, Minori; Maťoška, Václav; Bauer, Peter; Oyama, Fumitaka

doi:10.1002/1873-3468.12798

Cited by 14 publications

(6 citation statements)

References 32 publications

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“…Similar to chitotriosidase the other active chitinase in mammals and also a GH18 chitinase, we observe an apparent reduction in the rate of mAMCase catalysis across all pH values measured at 4MU-chitobioside concentrations above 80 μM, which suggests that mAMCase may be subject to product inhibition 22 . The underlying mechanism for the observed product inhibition may be that mAMCase can transglycosylate the products, as has been previously observed at pH 2.0 and 7.0 23 . This potential product inhibition leads to a systematic underprediction of rates by the Michaelis-Menten model at high substrate concentrations.…”

Section: Resultssupporting

confidence: 53%

Structural characterization of ligand binding and pH-specific enzymatic activity of mouse Acidic Mammalian Chitinase

Díaz

Ecker

Correy

et al. 2023

Preprint

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Chitin is an abundant biopolymer and pathogen-associated molecular pattern that stimulates a host innate immune response. Mammals express chitin-binding and chitin-degrading proteins to remove chitin from the body. One of these enzymes, Acidic Mammalian Chitinase (AMCase), is known for its ability to function under acidic conditions in the stomach but is also active in tissues with more neutral pHs, such as the lung. Here, we used a combination of biochemical, structural, and computational modeling approaches to examine how the mouse homolog (mAMCase) can act in both acidic and neutral environments. We defined kinetic properties of mAMCase activity across a broad pH range, quantifying its unusual dual activity optima at pH 2 and 7. We also solved high resolution crystal structures of mAMCase in complex with chitin, where we identified extensive conformational ligand heterogeneity. Leveraging these data, we conducted molecular dynamics simulations that suggest how a key catalytic residue could be protonated via distinct mechanisms in each of the two environmental pH ranges. These results integrate structural, biochemical, and computational approaches to deliver a more complete understanding of the catalytic mechanism governing mAMCase activity at different pH. Engineering proteins with tunable pH optima may provide new opportunities to develop improved enzyme variants, including AMCase, for therapeutic purposes in chitin degradation.

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Section: Resultssupporting

confidence: 53%

Structural characterization of ligand binding and pH-specific enzymatic activity of mouse Acidic Mammalian Chitinase

Díaz

Ecker

Correy

et al. 2023

Preprint

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“…Furthermore, supplementation of chitooligosaccharides can enhance the immune Interestingly, DD of the random-type chitosan affected the pH-dependence of the degradation rate (Figure 4A,B). We have previously reported that mouse Chia shows higher transglycosylation and weaker glycosidase activity under neutral conditions than at acidic pH [32]. Importantly, substrate degradation and transglycosylation by Chia can occur simultaneously.…”

Section: R Peer Review 8 Of 13mentioning

confidence: 95%

“…This method can separate and detect very low amounts (~pmol) of chitooligosaccharides according to their molecular weight, based on their differential migration rates through polyacrylamide gel [30,54,55]. The samples were quantified using the Luminescent Image Analyzer (Image-Quant LAS 4000, GE Healthcare, Piscataway, NJ, USA) as described previously [30,32,55].…”

Section: Analysis Of Chitooligosaccharides By Facementioning

confidence: 99%

“…Recombinant Chia has peak activity at a pH of around 2.0 that gradually decreases at more neutral conditions (pH 3.0-7.0), primarily producing (GlcNAc) 2 [28][29][30][31]. In addition, mouse Chia exhibits transglycosylation activity under neutral conditions [32]. Chia is resistant to digestion by proteases in mice, chickens, pigs, and common marmosets under gastrointestinal-like conditions [33][34][35][36][37].…”

Section: Introductionmentioning

confidence: 99%

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Mouse Acidic Chitinase Effectively Degrades Random-Type Chitosan to Chitooligosaccharides of Variable Lengths under Stomach and Lung Tissue pH Conditions

et al. 2021

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Chitooligosaccharides exhibit several biomedical activities, such as inflammation and tumorigenesis reduction in mammals. The mechanism of the chitooligosaccharides’ formation in vivo has been, however, poorly understood. Here we report that mouse acidic chitinase (Chia), which is widely expressed in mouse tissues, can produce chitooligosaccharides from deacetylated chitin (chitosan) at pH levels corresponding to stomach and lung tissues. Chia degraded chitin to produce N-acetyl-d-glucosamine (GlcNAc) dimers. The block-type chitosan (heterogenous deacetylation) is soluble at pH 2.0 (optimal condition for mouse Chia) and was degraded into chitooligosaccharides with various sizes ranging from di- to nonamers. The random-type chitosan (homogenous deacetylation) is soluble in water that enables us to examine its degradation at pH 2.0, 5.0, and 7.0. Incubation of these substrates with Chia resulted in the more efficient production of chitooligosaccharides with more variable sizes was from random-type chitosan than from the block-type form of the molecule. The data presented here indicate that Chia digests chitosan acquired by homogenous deacetylation of chitin in vitro and in vivo. The degradation products may then influence different physiological or pathological processes. Our results also suggest that bioactive chitooligosaccharides can be obtained conveniently using homogenously deacetylated chitosan and Chia for various biomedical applications.

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“…Lysozyme TG was also applied to the synthesis of novel inhibitors for hen egg-white lysozyme [ 55 ] and a plant elicitor-active oligosaccharides [ 56 ]. Like lysozyme, chitinases belonging to the GH18 family were reported to catalyze TG reactions with COSs [ 57 , 58 , 59 ]. In these enzymatic TG reactions, native enzymes with full intrinsic hydrolytic activities were used.…”

Section: Synthetic Strategies Of Coss With Promising Functionsmentioning

confidence: 99%

Green-Chemical Strategies for Production of Tailor-Made Chitooligosaccharides with Enhanced Biological Activities

Thomas,

Fukamizo,

Suginta

2023

Molecules

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Chitooligosaccharides (COSs) are b-1,4-linked homo-oligosaccharides of N-acetylglucosamine (GlcNAc) or glucosamine (GlcN), and also include hetero-oligosaccharides composed of GlcNAc and GlcN. These sugars are of practical importance because of their various biological activities, such as antimicrobial, anti-inflammatory, antioxidant and antitumor activities, as well as triggering the innate immunity in plants. The reported data on bioactivities of COSs used to contain some uncertainties or contradictions, because the experiments were conducted with poorly characterized COS mixtures. Recently, COSs have been satisfactorily characterized with respect to their structures, especially the degree of polymerization (DP) and degree of N-acetylation (DA); thus, the structure–bioactivity relationship of COSs has become more unambiguous. To date, various green-chemical strategies involving enzymatic synthesis of COSs with designed sequences and desired biological activities have been developed. The enzymatic strategies could involve transglycosylation or glycosynthase reactions using reducing end-activated sugars as the donor substrates and chitinase/chitosanase and their mutants as the biocatalysts. Site-specific chitin deacetylases were also proposed to be applicable for this purpose. Furthermore, to improve the yields of the COS products, metabolic engineering techniques could be applied. The above-mentioned approaches will provide the opportunity to produce tailor-made COSs, leading to the enhanced utilization of chitin biomass.

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Mouse acidic mammalian chitinase exhibits transglycosylation activity at somatic tissue pH

Cited by 14 publications

References 32 publications

Structural characterization of ligand binding and pH-specific enzymatic activity of mouse Acidic Mammalian Chitinase

Structural characterization of ligand binding and pH-specific enzymatic activity of mouse Acidic Mammalian Chitinase

Mouse Acidic Chitinase Effectively Degrades Random-Type Chitosan to Chitooligosaccharides of Variable Lengths under Stomach and Lung Tissue pH Conditions

Green-Chemical Strategies for Production of Tailor-Made Chitooligosaccharides with Enhanced Biological Activities

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