Purification and Characterization of Four β-Expansins (Zea m 1 Isoforms) from Maize Pollen

Li, Lian Chao; Bedinger, Patricia A.; Volk, Carol; Jones, A. Daniel; Cosgrove, Daniel J.

doi:10.1104/pp.103.020024

Cited by 97 publications

(124 citation statements)

References 53 publications

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“…This idea led Cosgrove and his colleagues to finally discover expansin proteins, which mediate acid wall extension without hydrolytic activity, from a series of plant walls (Cosgrove et al, 1997;Li, Z. C. et al, 1993;Li, L. C. et al, 2003;McQueen-Mason et al, 1992;Sampedro & Cosgrove, 2005). This study demonstrates that treating walls of C. cinerea with heating, protease or protein denaturants eliminated the acid-induced long-term wall extension activity of C. cinerea stipes exactly as seen in plant cell walls (Cosgrove, 1989), implying that this acid-induced stipe wall long-term extension is a proteinmediated process.…”

Section: Discussionmentioning

confidence: 99%

Characterization of stipe elongation of the mushroom Coprinopsis cinerea

Zhang

Zhou

et al. 2014

Microbiology

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Previously, we observed an acid-induced short-term wall extension in Flammulina velutipes apical stipes during a 15 min period after a change from a neutral to an acidic pH. This acid-induced stipe wall extension was eliminated by heating and reconstituted by a snail expansin-like protein, although we failed to isolate any endogenous expansin-like protein from F. velutipes because of its limited 1 mm fast elongation region. In this study, we report that Coprinopsis cinerea stipes possess a 9 mm fast elongation apical region, which is suitable as a model material for wall extension studies. The elongating apical stipe showed two phases of acid-induced wall extension, an initial quick short-term wall extension during the first 15 min and a slower, gradually decaying long-term wall extension over the subsequent 2 h. After heating or protein inactivation pretreatment, apical stipes lost the long-term wall extension, retaining a slower short-term wall extension, which was reconstituted by an expansin-like snail protein. In contrast, the non-elongating basal stipes showed only a weaker short-term wall extension. We propose that the long-term wall extension is a protein-mediated process involved in stipe elongation, whereas the short-term wall extension is a non-protein mediated process not involved in stipe elongation.

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Section: Discussionmentioning

confidence: 99%

Characterization of stipe elongation of the mushroom Coprinopsis cinerea

Zhang

Zhou

et al. 2014

Microbiology

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“…5, clamped in a constant-force extensometer at 20-gram force in 50 mM sodium acetate (pH 5.5). Specimen length was recorded at 30-s intervals (23,36) before and after addition of recombinant EXLX1 or native EXPB1 purified from maize pollen (37).…”

Section: Methodsmentioning

confidence: 99%

Crystal structure and activity of Bacillus subtilis YoaJ (EXLX1), a bacterial expansin that promotes root colonization

Kerff

Amoroso

Herman

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

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185

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We solved the crystal structure of a secreted protein, EXLX1, encoded by the yoaJ gene of Bacillus subtilis. Its structure is remarkably similar to that of plant ␤-expansins (group 1 grass pollen allergens), consisting of 2 tightly packed domains (D1, D2) with a potential polysaccharide-binding surface spanning the 2 domains. Domain D1 has a double-␤-barrel fold with partial conservation of the catalytic site found in family 45 glycosyl hydrolases and in the MltA family of lytic transglycosylases. Domain D2 has an Ig-like fold similar to group 2/3 grass pollen allergens, with structural features similar to a type A carbohydratebinding domain. EXLX1 bound to plant cell walls, cellulose, and peptidoglycan, but it lacked lytic activity against a variety of plant cell wall polysaccharides and peptidoglycan. EXLX1 promoted plant cell wall extension similar to, but 10 times weaker than, plant ␤-expansins, which synergistically enhanced EXLX1 activity. Deletion of the gene encoding EXLX1 did not affect growth or peptidoglycan composition of B. subtilis in liquid medium, but slowed lysis upon osmotic shock and greatly reduced the ability of the bacterium to colonize maize roots. The presence of EXLX1 homologs in a small but diverse set of plant pathogens further supports a role in plant-bacterial interactions. Because plant expansins have proved difficult to express in active form in heterologous systems, the discovery of a bacterial homolog opens the door for detailed structural studies of expansin function.family 45 endoglucanase ͉ lytic transglycosylase ͉ peptidoglycan ͉ plant cell wall ͉ plant-microbe interactions B acterial and plant cell walls have similar functions but distinctive structures. Bacterial peptidoglycan forms a network of linear polysaccharide strands of alternating Nacetylglucosamine (GlcNAc) and N-acetylmuramic acid (MurNAc) residues cross-linked by short polypeptides. As a giant bag-shaped sacculus, peptidoglycan expands via the action of endopeptidases, amidases, and lytic transglycosylases that cleave covalent bonds and allow insertion of new subunits (1). In contrast, the growing plant cell wall is formed from a scaffold of cellulose microfibrils tethered together by branched glycans such as xyloglucan or arabinoxylan that bind noncovalently to cellulose surfaces. The cellulose-hemicellulose network enlarges via polymer slippage or ''creep,'' mechanically powered by turgorgenerated forces in the cell wall and catalyzed by expansins and other wall-loosening agents (2).Expansins are known principally from plants where they function in cell enlargement and other developmental events requiring cell wall loosening (3). Canonical expansins are small proteins (Ϸ26 kDa, Ϸ225 aa) consisting of 2 compact domains: D1 has a fold similar to that of family 45 glycosyl hydrolases (GH45), and D2 has a ␤-sandwich fold. Expansins facilitate cell wall creep without breakdown of wall polymers (3-5). Plant expansins consist of 2 major families: ␣-expansins, which preferentially loosen the cell walls of dicots compa...

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“…S2A and Table III), class III peroxidase has been known as a heme-containing glycoprotein (42). Polygalacturonase, pollen-specific protein C13 (Os09g39950), ␤-expansin Os-EXPB13, and ␤-expansin have been well documented as pollen allergens (43)(44)(45). Previous investigations showed that most pollen allergens were glycoproteins, whereas glycan probably contributes to their allergenic activity (46).…”

Section: Identification Of Proteins Involved In Pollen Germinationmentioning

confidence: 99%

Proteomics Identification of Differentially Expressed Proteins Associated with Pollen Germination and Tube Growth Reveals Characteristics of Germinated Oryza sativa Pollen

Dai

Chen

Chong

et al. 2007

Molecular & Cellular Proteomics

139

134

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Mature pollen from most plant species is metabolically quiescent; however, after pollination, it germinates quickly and gives rise to a pollen tube to transport sperms into the embryo sac. Because methods for collecting a large amount of in vitro germinated pollen grains for transcriptomics and proteomics studies from model plants of Arabidopsis and rice are not available, molecular information about the germination developmental process is lacking. Here we describe a method for obtaining a large quantity of in vitro germinating rice pollen for proteomics study. Two-dimensional electrophoresis of ϳ2300 protein spots revealed 186 that were differentially expressed in mature and germinated pollen. Most showed a changed level of expression, and only 66 appeared to be specific to developmental stages. Furthermore 160 differentially expressed protein spots were identified on mass spectrometry to match 120 diverse protein species. These proteins involve different cellular and metabolic processes with obvious functional skew toward wall metabolism, protein synthesis and degradation, cytoskeleton dynamics, and carbohydrate/energy metabolism. Wall metabolism-related proteins are prominently featured in the differentially expressed proteins and the pollen proteome as compared with rice sporophytic proteomes. Our study also revealed multiple isoforms and differential expression patterns between isoforms of a protein. These results provide novel insights into pollen function specialization. Pollen of flowering plants, generated in diploid sporophytic plants via meiosis followed by two cycles of mitosis, contains three haploid genomes and is a highly reduced organism. Mature pollen grains from most plant species are metabolically quiescent. However, during pollination, they can quickly germinate and give rise to a polarly growing pollen tube whereby the pollen interacts with pistils and then delivers two sperms into the embryo sac to initiate double fertilization. Besides having biological importance, pollen germination and tube growth have been considered unique developmental processes for studying cell polar establishment, cell differentiation, cell fate determination, and cell-to-cell recognition. Thus, the molecular mechanisms underlining the specific cellular programs have been the focus of investigation over the past 50 years (1). However, until now, only a limited number of genes encoding coat/wall proteins or signal molecules have been shown to be essential for pollen germination, tube growth, and interaction of the tube and stigma (1-7).Recent analyses of mature pollen of Arabidopsis revealed the transcriptome to have reduced complexity and a higher proportion of selectively expressed transcripts than sporophytic tissues (8 -10). As well, about one-third of the genes expressed in vegetative tissues are not expressed in the pollen (8). The observation suggests that the transcriptional characteristics involve pollen function specialization. Furthermore these studies determined that pollen transcriptome has a functiona...

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Purification and Characterization of Four β-Expansins (Zea m 1 Isoforms) from Maize Pollen

Cited by 97 publications

References 53 publications

Characterization of stipe elongation of the mushroom Coprinopsis cinerea

Characterization of stipe elongation of the mushroom Coprinopsis cinerea

Crystal structure and activity of Bacillus subtilis YoaJ (EXLX1), a bacterial expansin that promotes root colonization

Proteomics Identification of Differentially Expressed Proteins Associated with Pollen Germination and Tube Growth Reveals Characteristics of Germinated Oryza sativa Pollen

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