Peanut agglutinin (PNA) is plant

lectin Lectins are carbohydrate-binding proteins that are highly specific for sugar Moiety (chemistry), groups that are part of other molecules, so cause agglutination (biology), agglutination of particular cells or precipitation of glycoconjugates an ...

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...

derived from the

fruit In botany, a fruit is the seed-bearing structure in flowering plants (angiosperms) that is formed from the ovary after flowering. Fruits are the means by which angiosperms disseminate their seeds. Edible fruits in particular have long propaga ...

s of '' Arachis hypogaea''. Peanut agglutinin may also be referred to as ''Arachis hypogaea'' lectin. Lectins recognise and bind particular

sugar Sugar is the generic name for sweet-tasting, soluble carbohydrates, many of which are used in food. Simple sugars, also called monosaccharides, include glucose Glucose is a sugar with the Chemical formula#Molecular formula, molecul ...

sequences in carbohydrates; peanut agglutinin binds the carbohydrate sequence Gal-β(1-3)- GalNAc. The name "peanut agglutinin" originates from its ability to stick together ( agglutinate) cells, such as

neuraminidase Exo-α-sialidase (, sialidase, neuraminidase; systematic name acetylneuraminyl hydrolase) is a glycoside hydrolase that cleaves the glycosidic linkages of neuraminic acids: : Hydrolysis of α-(2→3)-, α-(2→6)-, α-(2→8)- glycosidic linkag ...

-treated

erythrocytes Red blood cells (RBCs), referred to as erythrocytes (, with -''cyte'' translated as 'cell' in modern usage) in academia and medical publishing, also known as red cells, erythroid cells, and rarely haematids, are the most common type of blood cel ...

, which have

glycoprotein Glycoproteins are proteins which contain oligosaccharide (sugar) chains covalently attached to amino acid side-chains. The carbohydrate is attached to the protein in a cotranslational or posttranslational modification. This process is known a ...

s or

glycolipid Glycolipids () are lipids with a carbohydrate attached by a glycosidic (covalent) bond. Their role is to maintain the stability of the cell membrane and to facilitate cellular recognition, which is crucial to the immune response and in the c ...

s on their surface which include the Gal-β(1-3)-GalNAc carbohydrate sequence.

Structure

The protein is 273 amino acids in length with the first 23 residues acting as a signal peptide which is subsequently cleaved. It has a

Uniprot UniProt is a freely accessible database of protein sequence and functional information, many entries being derived from genome sequencing projects. It contains a large amount of information about the biological function of proteins derived fro ...

accession o
P02872
There are over 20 structures of this protein in the PDB which reveal and all

beta-sheet The beta sheet (β-sheet, also β-pleated sheet) is a common structural motif, motif of the regular protein secondary structure. Beta sheets consist of beta strands (β-strands) connected laterally by at least two or three backbone chain, backbon ...

protein with a tetrameric quaternary structure. It is a member of the Lectin_legB PFAM family.
Available Structures of peanut agglutinin

Uses in cell biology and biochemistry

Because peanut agglutinin specifically binds a particular carbohydrate sequence it finds use in a range of methods for

cell biology Cell biology (also cellular biology or cytology) is a branch of biology that studies the structure, function, and behavior of cells. All living organisms are made of cells. A cell is the basic unit of life that is responsible for the living an ...

and

biochemistry Biochemistry, or biological chemistry, is the study of chemical processes within and relating to living organisms. A sub-discipline of both chemistry and biology, biochemistry may be divided into three fields: structural biology, enzymology, a ...

. For example in PNA- affinity chromatography the binding specificity of peanut agglutinin is used to isolate glycosylated molecules which have the sugar sequence Gal-β(1-3)-GalNAc. Peanut agglutinin activity is inhibited by

lactose Lactose is a disaccharide composed of galactose and glucose and has the molecular formula C12H22O11. Lactose makes up around 2–8% of milk (by mass). The name comes from (Genitive case, gen. ), the Latin word for milk, plus the suffix ''-o ...

and

galactose Galactose (, ''wikt:galacto-, galacto-'' + ''wikt:-ose#Suffix 2, -ose'', ), sometimes abbreviated Gal, is a monosaccharide sugar that is about as sweetness, sweet as glucose, and about 65% as sweet as sucrose. It is an aldohexose and a C-4 epime ...

which compete for the binding site. Other uses include: * Potent anti-

T cell T cells (also known as T lymphocytes) are an important part of the immune system and play a central role in the adaptive immune response. T cells can be distinguished from other lymphocytes by the presence of a T-cell receptor (TCR) on their cell ...

activity. * Distinguishing between human

lymphocyte A lymphocyte is a type of white blood cell (leukocyte) in the immune system of most vertebrates. Lymphocytes include T cells (for cell-mediated and cytotoxic adaptive immunity), B cells (for humoral, antibody-driven adaptive immunity), an ...

subsets. * Identification of

cone cell Cone cells or cones are photoreceptor cells in the retina of the vertebrate eye. Cones are active in daylight conditions and enable photopic vision, as opposed to rod cells, which are active in dim light and enable scotopic vision. Most v ...

inner and outer segments and to a lesser extent

rod cell Rod cells are photoreceptor cells in the retina of the eye that can function in lower light better than the other type of visual photoreceptor, cone cells. Rods are usually found concentrated at the outer edges of the retina and are used in ...

inner segments in the mammalian retina. *

Tumour A neoplasm () is a type of abnormal and excessive growth of tissue (biology), tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tiss ...

tissue determination for transitional

mucosa A mucous membrane or mucosa is a membrane that lines various cavities in the body of an organism and covers the surface of internal organs. It consists of one or more layers of epithelial cells overlying a layer of loose connective tissue. It ...

malignancies. * Identification of mammalian-infective metacyclic promastigote '' Leishmania major'' parasites from other life cycle forms also found in the

sandfly Sandfly or sand fly is a colloquial name for any species or genus of flying, biting, blood-sucking dipteran (fly) encountered in sandy areas. In the United States, ''sandfly'' may refer to certain horse flies that are also known as "greenhea ...

host. * Identification of the outer acrosome membrane in sperm, indicating acrosome integrity.

References

Plant lectins Legume lectins Glycoproteins Peanut products {{biochem-stub

Structure

Uses in cell biology and biochemistry

See also

References