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Difference between revisions of "Polysaccharide Lyase Family 22"

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== Substrate specificities ==
 
== Substrate specificities ==
Family 22 Polysaccharide Lyases (PL22s) contain two subfamilies <cite>Lombard2010</cite> and several outlier sequences. Originally referred to as oligogalacturonide trans-eliminases (OGTE)<cite>Moran1968</cite>, PL22s are now commonly referred to as oligogalacturonide lyases (OGLs).
+
Family 22 Polysaccharide Lyases (PL22s) contain two subfamilies and several outlier sequences <cite>Lombard2010</cite>. Originally referred to as oligogalacturonide trans-eliminases (OGTE)<cite>Moran1968</cite>, PL22s are now commonly referred to as oligogalacturonide lyases (OGLs).
  
 
As the name suggests, OGLs are preferentially active on short chain oligomers of galacturonides. PL22s are preferentially active on digalacturonate and Δ4,5-unsaturated digalacturonate <cite>Abbott2010</cite><cite>Kester1999</cite>. Activity on trigalacturonate has been shown to be significantly lower than on digalacturonate and although activity on the unsaturated dimer was lower than that of the saturated dimer, activity on Δ4,5-unsaturated trigalacturonate is comparable or higher than that of saturated trigalacturonate <cite>Kester1999</cite>. OGLs lack activity on long chain polymers of α-(1,4)-linked polygalacturonate. Activity has been demonstrated on methylated short chain galacturonides with differing levels of activity depending on the location of methylation <cite>Kester1999</cite>. Activity on 1-methyl digalacturonate was only half of what was seen on digalacturonate and no activity was found on 2-methyl digalacturonate. A similar trend was shown on trigalacturonate as well with roughly half the activity on 1-methyl trigalacturonate as on trigalacturonate and no activity on 2-methyl galacturonate.  
 
As the name suggests, OGLs are preferentially active on short chain oligomers of galacturonides. PL22s are preferentially active on digalacturonate and Δ4,5-unsaturated digalacturonate <cite>Abbott2010</cite><cite>Kester1999</cite>. Activity on trigalacturonate has been shown to be significantly lower than on digalacturonate and although activity on the unsaturated dimer was lower than that of the saturated dimer, activity on Δ4,5-unsaturated trigalacturonate is comparable or higher than that of saturated trigalacturonate <cite>Kester1999</cite>. OGLs lack activity on long chain polymers of α-(1,4)-linked polygalacturonate. Activity has been demonstrated on methylated short chain galacturonides with differing levels of activity depending on the location of methylation <cite>Kester1999</cite>. Activity on 1-methyl digalacturonate was only half of what was seen on digalacturonate and no activity was found on 2-methyl digalacturonate. A similar trend was shown on trigalacturonate as well with roughly half the activity on 1-methyl trigalacturonate as on trigalacturonate and no activity on 2-methyl galacturonate.  

Revision as of 06:46, 9 September 2014

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Polysaccharide Lyase Family PL22
3D Structure β7 propeller
Mechanism β-elimination
Charge neutraliser manganese
Active site residues known
CAZy DB link
http://www.cazy.org/PL22.html


Substrate specificities

Family 22 Polysaccharide Lyases (PL22s) contain two subfamilies and several outlier sequences [1]. Originally referred to as oligogalacturonide trans-eliminases (OGTE)[2], PL22s are now commonly referred to as oligogalacturonide lyases (OGLs).

As the name suggests, OGLs are preferentially active on short chain oligomers of galacturonides. PL22s are preferentially active on digalacturonate and Δ4,5-unsaturated digalacturonate [3][4]. Activity on trigalacturonate has been shown to be significantly lower than on digalacturonate and although activity on the unsaturated dimer was lower than that of the saturated dimer, activity on Δ4,5-unsaturated trigalacturonate is comparable or higher than that of saturated trigalacturonate [4]. OGLs lack activity on long chain polymers of α-(1,4)-linked polygalacturonate. Activity has been demonstrated on methylated short chain galacturonides with differing levels of activity depending on the location of methylation [4]. Activity on 1-methyl digalacturonate was only half of what was seen on digalacturonate and no activity was found on 2-methyl digalacturonate. A similar trend was shown on trigalacturonate as well with roughly half the activity on 1-methyl trigalacturonate as on trigalacturonate and no activity on 2-methyl galacturonate.


Kinetics and Mechanism

Catalytic Residues

The Brønstead base for PL22s is predicted to be a histidine [3]. H242 in YE1876 from Yersinia enterocolitica subsp. enterocolitica 8081 was the first and is to date, the only catalytic residue determined reported to be in proximity to the α-proton of galacturonate. This histidine is highly conserved within Family 22 lyases with only Candidatus Solibacter usitatus Ellin6076 (gi|116225114|) displaying a threonine (T236); however, whether this gene product functions as a lyase has yet to be determined.

The metal coordination pocket houses a manganese ion and is comprised of three histidines (VPA0088 H287, H353, H355; YeOGL H287, H353, H355) and one glutamine (VPA0088 Q350; YeOGL Q350). It is of note however, that although these residues are perfectly conserved in all reported subfamily 1 sequences and several outlier sequences, subfamily 2 or archaeal sequences display different signatures [1]. The archaeal sequences have conserved histidines but there is variations Q350. In subfamily 2, H287 is invariant; however, Q350 is not conserved and H353 and H355 have been replaced with a glutamate and asparagine respectively. These modifications likely alter the chemistry of metal coordination selectivity.


Three-dimensional structures

YePL22 in complex with Mn2+ and acetate

The first structure of a PL22 determined was the Vibrio parahaemolyticus RIMD 2210633 (PDB 3C5M) solved in 2008 by x-ray diffraction to 2.60 Å (http://www.nesg.org/, Northeast Structural Genomics Consortium). This was followed in 2010 by Yersinia enterocolitica subsp. enterocolitica 8081 (PDB 3PE7) which was solved in complex with Mn2+ and acetate by x-ray diffraction to 1.65 Å. The two proteins share ~69% sequence identity and highly similar 3D structures.


Family Firsts

First catalytic activity
OGTE from Pectobacterium carotovorum ICPB EC153 (previously Erwinia carotovora). [2]
First catalytic base identification
YeOGL (YE1876) H242 from Yersinia enterocolitica subsp. enterocolitica 8081. [3]
First catalytic divalent cation identification
OGL (Dda3937_03686) from Dickeya Dadantii 3937 (previously Erwinia chrysanthemi 3937). [5].
First 3-D structure
VPA0088 from Vibrio parahaemolyticus RIMD 2210633. (PDB 3C5M)

References

  1. Lombard V, Bernard T, Rancurel C, Brumer H, Coutinho PM, and Henrissat B. (2010). A hierarchical classification of polysaccharide lyases for glycogenomics. Biochem J. 2010;432(3):437-44. DOI:10.1042/BJ20101185 | PubMed ID:20925655 [Lombard2010]
  2. Moran F, Nasuno S, and Starr MP. (1968). Oligogalacturonide trans-eliminase of Erwinia carotovora. Arch Biochem Biophys. 1968;125(3):734-41. DOI:10.1016/0003-9861(68)90508-0 | PubMed ID:5671040 [Moran1968]
  3. Abbott DW, Gilbert HJ, and Boraston AB. (2010). The active site of oligogalacturonate lyase provides unique insights into cytoplasmic oligogalacturonate beta-elimination. J Biol Chem. 2010;285(50):39029-38. DOI:10.1074/jbc.M110.153981 | PubMed ID:20851883 [Abbott2010]
  4. Kester HC, Magaud D, Roy C, Anker D, Doutheau A, Shevchik V, Hugouvieux-Cotte-Pattat N, Benen JA, and Visser J. (1999). Performance of selected microbial pectinases on synthetic monomethyl-esterified di- and trigalacturonates. J Biol Chem. 1999;274(52):37053-9. DOI:10.1074/jbc.274.52.37053 | PubMed ID:10601263 [Kester1999]
  5. Shevchik VE, Condemine G, Robert-Baudouy J, and Hugouvieux-Cotte-Pattat N. (1999). The exopolygalacturonate lyase PelW and the oligogalacturonate lyase Ogl, two cytoplasmic enzymes of pectin catabolism in Erwinia chrysanthemi 3937. J Bacteriol. 1999;181(13):3912-9. DOI:10.1128/JB.181.13.3912-3919.1999 | PubMed ID:10383957 [Shevchik1989]
  6. Collmer A and Bateman DF. (1981). Impaired induction and self-catabolite repression of extracellular pectate lyase in Erwinia chrysanthemi mutants deficient in oligogalacturonide lyase. Proc Natl Acad Sci U S A. 1981;78(6):3920-4. DOI:10.1073/pnas.78.6.3920 | PubMed ID:16593039 [Collmer1981]
  7. Reverchon S and Robert-Baudouy J. (1987). Molecular cloning of an Erwinia chrysanthemi oligogalacturonate lyase gene involved in pectin degradation. Gene. 1987;55(1):125-33. DOI:10.1016/0378-1119(87)90255-1 | PubMed ID:3623103 [Reverchon1987]
  8. Reverchon S, Huang Y, Bourson C, and Robert-Baudouy J. (1989). Nucleotide sequences of the Erwinia chrysanthemi ogl and pelE genes negatively regulated by the kdgR gene product. Gene. 1989;85(1):125-34. DOI:10.1016/0378-1119(89)90472-1 | PubMed ID:2695393 [Reverchon1989]
  9. Yang S, Zhang Q, Guo J, Charkowski AO, Glick BR, Ibekwe AM, Cooksey DA, and Yang CH. (2007). Global effect of indole-3-acetic acid biosynthesis on multiple virulence factors of Erwinia chrysanthemi 3937. Appl Environ Microbiol. 2007;73(4):1079-88. DOI:10.1128/AEM.01770-06 | PubMed ID:17189441 [Yang2007]

All Medline abstracts: PubMed