Plant Proteins, Peptides and Antigens

The pH is an important parameter controlling many metabolic and signalling pathways in living cells. Recombinant fluorescent pH indicators (pHluorins) have come into vogue for monitoring cellular pH. They are derived from the most popular Aequorea victoria GFP (Av-GFP). Here, we present a novel fluorescent pH reporter protein from the orange seapen Ptilosarcus gurneyi (Pt-GFP) and compare its properties with pHluorins for expression and use in plants. - [Read A Novel Fluorescent pH Probe for Expression in Plants]

BN-PAGE has become the method of choice for the investigation of the respiratory protein complexes of the electron transfer chains of a range of organisms. It allows the separation in two dimensions of extremely hydrophobic protein sets for analysis and also provides information on their native interactions. In this review we discuss the capabilities of BN-PAGE in proteomics and the wider investigation of protein:protein interactions with a focus on its use and potential in plant science. - [Read Blue-Native PAGE in Plants: A Tool in Analysis of Protein-Protein Interactions]

Protocol on the extraction and solubilization of total protein from plant seeds. - [Read Extraction and Solubilization of Total Protein from Plant Seeds Protocol]

Protocol describes a method for performing isoelectric fractionation of a maize embryo sample using a multicompartment electrolyzer(MCE). This prefractionation of proteins having pIs within a certain pH interval is essential for allowing high loads of protein to be resolved on narrow and ultra-narrow immobilized pH gradients used in 2D electrophoresis. The isoelectric membranes in the MCE act like isoelectric traps capturing all the protein species having pIs encompassing the pI value of each... - [Read Fractionation of Maize Embryo Proteins for 2-D Gel Electrophoresis Using Multicompartment Electrolyz]

The activity of ß-glucuronidase (GUS) can be accurately determined in intact plant tissue using 4-methylumbelliferyl ß-D-glucuronide (4-MUG) as a substrate. Upon hydrolysis by GUS, the fluorochrome 4-methyl umbelliferone (4-MU) is produced. This method is based on the permeability of both 4-MUG and 4-MU through plant tissue. It consists of incubation of the tissue with the reagent and quantification of the fluorescence emitted by 4-MU in the solution. GUS activity in each sample can be... - [Read Quantitative GUS Activity Assay in Intact Plant Tissue Protocol]

Using excitation at 365 nm and measuring emission at 455 nm, the amount of 4-MU produced can be quantified. Under these conditions, background fluorescence from the substrate is negligible, especially if the appropriate filter is selected. - [Read Quantitative GUS Activity Assay of Plant Extracts]

GUS is used as a tag to address nuclear localization whereas GFP is more versatile. GFP is detectable directly in living cells, GUS is only detected indirectly by staining of fixed tissue which may lead to artifacts or may obscure problems with protein solubility. In this protocol, protein localization is routinely assayed after particle-mediated transient transformation of onion epidermal cells. With this method it can be determined rapidly whether a given fusion protein is active and.... - [Read Subcellular Localization of GUS- and GFP-Tagged Proteins in Onion Epidermal Cells]