C5G6D7 · CABC2_BACT4
- ProteinChondroitin sulfate ABC exolyase
- Genechonabc
- StatusUniProtKB reviewed (Swiss-Prot)
- Organism
- Amino acids1014 (go to sequence)
- Protein existenceEvidence at protein level
- Annotation score5/5
Function
function
Broad-specificity glycosaminoglycan lyase, which acts in an exolytic fashion degrading chondroitin sulfates and dermatan sulfate to yield only disaccharide products. Has a preference for chondroitin 4-sulfate over chondroitin 6-sulfate. Has extremely low activity against hyaluronic acid. Is not active against acharan sulfate, heparin or heparan sulfate.
Catalytic activity
Cofactor
Mg2+ (UniProtKB | Rhea| CHEBI:18420 )
Note: Divalent metal cation. Requires divalent metal cation for binding of dermatan sulfate substrate, whereas it is not necessary for the binding of chondroitin sulfate substrates. Prefers Ca2+ or Mg2+, binding 1 ion per subunit.
Activity regulation
Specific activity for chondroitin sulfate substrates increases moderately (2-fold) while an increase of 25-fold is observed for dermatan sulfate as substrate upon addition of Ca2+ or Mg2+ ions (PubMed:18227125).
Increasing the concentration of Na+, K+ or Cs+ chloride from 0 to 0.1 M, increases the activity against all substrates. Further increases in salt concentration reduces the activity dramatically, with 50% inhibition occurring at 0.15 M and nearly complete inhibition at 0.4 M salt. The addition of 10 mM Ca2+ or Mg2+ ions increases the activity against chondroitin 4- and 6-sulfates by 2-3-fold, while the activity against dermatan sulfate increases much more significantly by 50-fold (PubMed:18512954).
Addition of Mn2+ and Zn2+ reduces activity against chondroitin sulfate substrates, but increases the activity against dermatan sulfate. Increasing the concentration of CaCl2 with both chondroitin 4- and 6-sulfates from 0 to 0.04 M increases the activity. A further increase reduces activity, with 50% inhibition at 0.065-0.085 M and a complete inhibition of the reaction at 0.2 M. In case of dermatan sulfate, the addition of low concentration of CaCl2 dramatically increases the activity from the basal level. The maximal activity is reached at 0.01 M CaCl2.
Increasing the concentration of Na+, K+ or Cs+ chloride from 0 to 0.1 M, increases the activity against all substrates. Further increases in salt concentration reduces the activity dramatically, with 50% inhibition occurring at 0.15 M and nearly complete inhibition at 0.4 M salt. The addition of 10 mM Ca2+ or Mg2+ ions increases the activity against chondroitin 4- and 6-sulfates by 2-3-fold, while the activity against dermatan sulfate increases much more significantly by 50-fold (PubMed:18512954).
Addition of Mn2+ and Zn2+ reduces activity against chondroitin sulfate substrates, but increases the activity against dermatan sulfate. Increasing the concentration of CaCl2 with both chondroitin 4- and 6-sulfates from 0 to 0.04 M increases the activity. A further increase reduces activity, with 50% inhibition at 0.065-0.085 M and a complete inhibition of the reaction at 0.2 M. In case of dermatan sulfate, the addition of low concentration of CaCl2 dramatically increases the activity from the basal level. The maximal activity is reached at 0.01 M CaCl2.
Kinetics
KM | SUBSTRATE | pH | TEMPERATURE[C] | NOTES | EVIDENCE | |
---|---|---|---|---|---|---|
67 μM | chondroitin 4-sulfate from porcine or bovine trachea | 7.6 | 37 | |||
33 μM | chondroitin 6-sulfate from shark cartilage | 7.6 | 37 | |||
61 μM | dermatan sulfate from porcine intestinal mucosa | 7.6 | 37 |
Vmax | pH | TEMPERATURE[C] | NOTES | EVIDENCE | |
---|---|---|---|---|---|
77.6 μmol/min/mg | 7.6 | 37 | with chondroitin 4-sulfate from bovine trachea as substrate, in 50 mM phosphate | ||
47.4 μmol/min/mg | 7.6 | 37 | with chondroitin 6-sulfate from shark cartilage as substrate, in 50 mM phosphate | ||
14.4 μmol/min/mg | 7.6 | 37 | with chondroitin 2,6-sulfate from skate cartilage as substrate, in 50 mM phosphate | ||
28.5 μmol/min/mg | 7.6 | 37 | with chondroitin 4,6-sulfate from squid cartilage as substrate, in 50 mM phosphate | ||
9.1 μmol/min/mg | 7.6 | 37 | with dermatan sulfate from porcine intestinal mucosa as substrate, in 50 mM phosphate |
kcat is 15792 min-1 with chondroitin 4-sulfate from porcine or bovine trachea as substrate. kcat is 10404 min-1 with chondroitin 6-sulfate from shark cartilage as substrate. kcat is 2307 min-1 with dermatan sulfate from porcine intestinal mucosa as substrate.
pH Dependence
Optimum pH is 7.6. Decreased activity at pH values below 7.0 and above 8.0. The activity against chondroitin 6-sulfate remains higher than with other substrates at low pH. At pH 6.5 the enzyme exhibits almost 60% of its maximal activity against chondroitin 6-sulfate, only 20% activity against chondroitin 4-sulfate and no measurable activity against dermatan sulfate. In contrast, at pH of 8.5 about 30% of enzyme's maximal activity against all substrates is displayed.
Temperature Dependence
Optimum temperature is 37 degrees Celsius. No significant reduction in activity at temperatures in the range of 25-40 degrees Celsius. At 50 degrees Celsius, activity of 45% for dermatan sulfate, 60% for chondroitin 4-sulfate and 75% for chondroitin 6-sulfate is detected. Thermal denaturation curve is bimodal with two consecutive thermal denaturation midpoints (Tm) corresponding to 44 and 50 degrees Celsius, respectively.
Features
Showing features for binding site, site, active site.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Binding site | 24 | Ca2+ (UniProtKB | ChEBI) | ||||
Sequence: S | ||||||
Binding site | 26 | Ca2+ (UniProtKB | ChEBI) | ||||
Sequence: E | ||||||
Binding site | 50 | Ca2+ (UniProtKB | ChEBI) | ||||
Sequence: D | ||||||
Binding site | 53 | Ca2+ (UniProtKB | ChEBI) | ||||
Sequence: H | ||||||
Binding site | 161 | Ca2+ (UniProtKB | ChEBI) | ||||
Sequence: D | ||||||
Site | 172 | Important for catalytic activity against all substrates | ||||
Sequence: R | ||||||
Site | 344 | Important for catalytic activity against dermatan sulfate substrate | ||||
Sequence: H | ||||||
Active site | 345 | Proton acceptor | ||||
Sequence: H | ||||||
Active site | 454 | Proton acceptor | ||||
Sequence: H | ||||||
Active site | 461 | Proton donor | ||||
Sequence: Y | ||||||
Site | 514 | Transition state stabilizer | ||||
Sequence: R | ||||||
Site | 628 | Important for catalytic activity against all substrates | ||||
Sequence: E |
GO annotations
Aspect | Term | |
---|---|---|
Cellular Component | extracellular region | |
Cellular Component | periplasmic space | |
Molecular Function | calcium ion binding | |
Molecular Function | carbohydrate binding | |
Molecular Function | chondroitin-sulfate-ABC endolyase activity | |
Molecular Function | chondroitin-sulfate-ABC exolyase activity | |
Molecular Function | magnesium ion binding | |
Biological Process | carbohydrate metabolic process | |
Biological Process | dermatan sulfate catabolic process | |
Biological Process | glycosaminoglycan catabolic process |
Keywords
- Molecular function
- Biological process
- Ligand
Enzyme and pathway databases
Protein family/group databases
Names & Taxonomy
Protein names
- Recommended nameChondroitin sulfate ABC exolyase
- EC number
- Alternative names
Gene names
Organism names
- Organism
- Strain
- Taxonomic lineageBacteria > Bacteroidota > Bacteroidia > Bacteroidales > Bacteroidaceae > Bacteroides
Accessions
- Primary accessionC5G6D7
Subcellular Location
Phenotypes & Variants
Features
Showing features for mutagenesis.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Mutagenesis | 172 | Loss of activity against all substrates. | ||||
Sequence: R → A | ||||||
Mutagenesis | 173 | Reduced activity against all substrates by a factor of about 2-10. | ||||
Sequence: Q → A | ||||||
Mutagenesis | 267 | Reduced activity against all substrates by a factor of about 2-10. | ||||
Sequence: R → A | ||||||
Mutagenesis | 344 | No detectable activity against dermatan sulfate in the standard assay, but after overnight incubation shows traces of degradation products, also still degrades chondroitin sulfate albeit with 10- to 30-fold lower catalytic efficiency. | ||||
Sequence: H → A | ||||||
Mutagenesis | 344 | Loss of activity against all substrates. | ||||
Sequence: H → D or E | ||||||
Mutagenesis | 344 | Retains 5-25% catalytic efficiency against all substrates. | ||||
Sequence: H → N | ||||||
Mutagenesis | 344 | Retains 5% catalytic efficiency against chondroitin 4-sulfate only. | ||||
Sequence: H → Q | ||||||
Mutagenesis | 345 | No activity against dermatan sulfate even after overnight incubation, but still degrades chondroitin sulfate albeit with 10- to 30-fold lower catalytic efficiency. | ||||
Sequence: H → A | ||||||
Mutagenesis | 345 | Loss of activity against all substrates. | ||||
Sequence: H → D or E | ||||||
Mutagenesis | 345 | Low levels of activity against chondroitin sulfate substrates, but no activity against dermatan sulfate. | ||||
Sequence: H → N or Q | ||||||
Mutagenesis | 453 | Slightly reduced activity against all substrates. | ||||
Sequence: H → A | ||||||
Mutagenesis | 453 | Shows no activity against dermatan sulfate while retaining about 10% of its catalytic efficiency against chondroitin 4- and 6-sulfates. | ||||
Sequence: H → N | ||||||
Mutagenesis | 454 | Loss of activity against all substrates. | ||||
Sequence: H → A, D, N, or Q | ||||||
Mutagenesis | 461 | Loss of activity against all substrates. | ||||
Sequence: Y → A | ||||||
Mutagenesis | 514 | Loss of activity against all substrates. | ||||
Sequence: R → A | ||||||
Mutagenesis | 628 | Loss of activity against all substrates. | ||||
Sequence: E → A or D | ||||||
Mutagenesis | 628 | Retains low levels of activity against chondroitin sulfate substrates, but not against dermatan sulfate as substrate. | ||||
Sequence: E → Q |
PTM/Processing
Features
Showing features for signal, chain.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Signal | 1-14 | |||||
Sequence: MLILSFLCPAFLNA | ||||||
Chain | PRO_0000420123 | 15-1014 | Chondroitin sulfate ABC exolyase | |||
Sequence: QIVTDERMFSFEEPQLPACITGVQSQLGISGAHYKDGKHSLEWTFEPNGRLELRKDLKFEKKDPTGKDLYLSAFIVWIYNEQPQDAAIEFEFLKDGRKCASFPFGINFKGWRAAWVCYERDMQGTPEEGMNELRIVAPDAKGRLFIDHLITATKVDARQQTADLQVPFVNAGTTNHWLVLYKHSLLKPDIELTPVSDKQRQEMKLLEKRFRDMIYTKGKVTEKEAETIRKKYDLYQITYKDGQVSGVPVFMVRASEAYERMIPDWDKDMLTKMGIEMRAYFDLMKRIAVAYNNSEAGSPIRKEMRRKFLAMYDHITDQGVAYGSCWGNIHHYGYSVRGLYPAYFLMKDVLREEGKLLEAERTLRWYAITNEVYPKPEGNGIDMDSFNTQTTGRIASILMMEDTPEKLQYLKSFSRWIDYGCRPAPGLAGSFKVDGGAFHHRNNYPAYAVGGLDGATNMIYLFSRTSLAVSELAHRTVKDVLLAMRFYCNKLNFPLSMSGRHPDGKGKLVPMHYAIMAIAGTPDGKGDFDKEMASAYLRLVSSDSSSAEQAPEYMPKVSNAQERKIAKRLVENGFRAEPDPQGNLSLGYGCVSVQRRENWSAVARGHSRYLWAAEHYLGHNLYGRYLAHGSLQILTAPPGQTVTPTTSGWQQEGFDWNRIPGVTSIHLPLDLLKANVLNVDTFSGMEEMLYSDEAFAGGLSQGKMNGNFGMKLHEHDKYNGTHRARKSFHFIDGMIVCLGSDIENTNMDYPTETTIFQLAVTDKAAHDYWKNNAGEGKVWMDHLGTGYYVPVAARFEKNFPQYSRMQDTGKETKGDWVSLIIDHGKAPKAGSYEYAILPGTDRKTMTAFAKKPAYSVLQQDRNAHILESPSDRITSYVLFETPQSLLPGGLLQRTDTSCLVMVRKESADKVLLTVAQPDLALYRGPSDEAFDKDGKRMERSIYSRPWIDNESGEIPVTVTLKGRWKVVETPYCKVVSEDKKQTVLRFLCKDGASYEVELEK |
Interaction
Subunit
Monomer.
Structure
Sequence
- Sequence statusComplete
- Sequence processingThe displayed sequence is further processed into a mature form.
- Length1,014
- Mass (Da)114,921
- Last updated2012-10-31 v2
- Checksum10C46B91CF02A44A
Sequence caution
Keywords
- Technical term