Part:BBa_K4382008

Pectin Methyl Esterase (Pme)

It is used to break the ester bonds in pectin.

Usage and Biology

Pectin methyl esterase is an enzyme whose function is to demethylate and deesterify pectic substances.Commercially pectinases are used immensely in the fruit industry for clarification of juices, firming of fruits and vegetables and production of low sugar jams and jellies. De-esterification of homogalacturonan (HG) is thought to stiffen pectin gels and primary cell walls by increasing calcium cross-linking between HG chains. Pectin is one of the vital cell wall components and homogalacturonan (HG) constitutes ~65% of total pectin present and it is the most abundant pectic polysaccharide in primary cell walls. HG consists of an α-1,4-linked D-galacturonic acid (GalA) backbone where the C6 atom is highly methyl-esterified.Its degree (and pattern) of methylation (DM) has been shown to affect biomechanical properties of the cell wall by making pectin susceptible for enzymatic de-polymerization and enabling gel formation. Pectin methyl esterases (PMEs) catalyze the specific de-methyl esterification of HG, releasing methanol and protons, and creating negatively charged carboxyl groups in the process.The demethylesterified HGA can either form Ca2+ bonds, which promote the formation of the so-called ‘egg-box’ model structure, thus forming gels, or become a target for pectin-degrading enzymes, such as polygalacturonases. Thus, PMEs have major roles in pectin remodelling.In the context of our project,the pectin methyl esterase will loosen up the cell wall so that pectate lyase(pelB-B2,BBa_K4382006) and pectin lyase (pelA,BBa_K4382007) can degrade the pectin present in the cell wall.

References

1. PELLOUX, J., RUSTERUCCI, C., & MELLEROWICZ, E. (2007). New insights into pectin methylesterase structure and function. Trends in Plant Science, 12(6), 267–277.

2. Micheli, F. (2001). Pectin methylesterases: Cell wall enzymes with important roles in plant physiology. Trends in Plant Science, 6(9), 414–419. https://doi.org/10.1016/s1360-1385(01)02045-3

3. Wang, X., Wilson, L., & Cosgrove, D. J. (2020). Pectin methylesterase selectively softens the onion epidermal wall yet reduces acid-induced creep. Journal of Experimental Botany, 71(9), 2629–2640. https://doi.org/10.1093/jxb/eraa059

Sequence and Features

Assembly Compatibility:

• 10
  INCOMPATIBLE WITH RFC[10]

  Illegal PstI site found at 48
  
• 12
  INCOMPATIBLE WITH RFC[12]

  Illegal PstI site found at 48
  
• 21
  INCOMPATIBLE WITH RFC[21]

  Illegal BamHI site found at 192
  Illegal BamHI site found at 1080
  
• 23
  INCOMPATIBLE WITH RFC[23]

  Illegal PstI site found at 48
  
• 25
  INCOMPATIBLE WITH RFC[25]

  Illegal PstI site found at 48
  Illegal NgoMIV site found at 343
  Illegal AgeI site found at 199
  
• 1000
  COMPATIBLE WITH RFC[1000]

Functional Parameters

biology	Ralstonia solanacearum
chassis	Bacillus subtilis 168
protein	Pme