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Optimization of Synthetic Proteins: Identification of Interpositional Dependencies Indicating Structurally and/or Functionally Linked Residues
Published on: July 14, 2015
Extensin: repetitive motifs, functional sites, post-translational codes, and phylogeny
M J Kieliszewski1, D T Lamport
1Complex Carbohydrate Research Center, University of Georgia, Athens 30602.
The Plant Journal : for Cell and Molecular Biology
|February 1, 1994
Summary
Plant extracellular matrix glycoproteins (HRGPs) self-assembly relies on post-translational modifications. Understanding these modifications and peptide motifs reveals HRGP functions in cell wall construction and evolution.
Area of Science:
- Plant Biology
- Molecular Botany
- Biochemistry
Background:
- Homologous hydroxyproline-rich glycoproteins (HRGPs) are crucial components of the plant extracellular matrix.
- HRGPs include extensins, repetitive proline-rich proteins (RPRPs), nodulins, gum arabic glycoprotein (GAGP), and arabinogalactan-proteins (AGPs).
- Their function in cell wall assembly and extension is intrinsically linked to post-translational modifications (PTMs).
Purpose of the Study:
- To elucidate the role of repetitive peptide motifs and PTMs in HRGP function.
- To explore the rules governing proline hydroxylation and glycosylation.
- To classify HRGPs based on their cross-linking capabilities and investigate their evolutionary relationships.
Main Methods:
- Analysis of repetitive peptide motifs within HRGPs, including X-Hypn, Pro-Hyp-Val-Tyr-Lys, Tyr-X-Tyr-Lys, and palindromic sequences.
- Investigation of post-translational modifications: hydroxylation, glycosylation, and cross-linking (intramolecular and intermolecular).
- Phylogenetic analysis to understand the evolutionary divergence of HRGP families.
Main Results:
- Specific peptide motifs are identified as functional sites for arabinosylation, rigidity enhancement, adhesion, and self-assembly nucleation.
- Emerging rules for proline hydroxylation and glycosylation are proposed, influenced by residue contiguity and specific motifs.
- HRGPs are functionally classified as cross-linking (CL) or non-cross-linking (NCL) extensins.
- Phylogenetic analysis suggests a series from basic RPRPs to acidic AGPs and indicates early divergence between monocot and dicot extensins.
Conclusions:
- HRGP function in cell wall assembly is dictated by their unique repetitive peptide motifs and extensive post-translational modifications.
- The study proposes rules for HRGP modification and classification, providing insights into their roles and evolutionary history.
- Understanding HRGP chemistry and evolution is key to comprehending plant cell wall structure and development.
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