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From 2011.igem.org

Latherin

Origin:

Latherin was first isolated in the 1980s by John Beeley and David Eckersall, from the University of Glasgow.

Latherin has since been found to be present in the salivary glands of horses, zebras, onagers and wild asses.

Natural Function:

Of the three species of mammal that are known to thermoregulate by sweating, horses are unique in having sweat with such a high concentration of protein and low concentration of salt. Latherin is the most abundant protein found in horse sweat and is believed to be the cause of the foaming appearance of the sweat on exercising horses.

Latherin has long been suspected to be involved in thermoregulation. The protein is absorbed readily at hydrophobic surfaces, allowing them to become wettable. It will also cause a reduction in water surface tension. This function is presumably linked to the protein’s ability to facilitate evaporation of sweat from the pelt.

Latherin has also been found in the saliva of several species of equids. Its proposed function here is to aid in the wetting of food, which in turn aids chewing and the ability of salivary enzymes to digest the food.

Sequence Data

Sequence analysis shows that latherin is a member of the PLUNC (“Palate, Lung and Nasal Epithelium Clone”) family. PLUNC represents a family of proteins, originally discovered in human. Their function is not entirely clear, but it is believed they may function in the innate immune response in the airways.

Analysis has shown that latherin has an unusual amino acid composition. The total number of hydrophobic amino acids is abnormally high, with leucine representing a large proportion of his. In fact, almost one in four residues is leucine. This is also true of the protein huPLUNC1, which has already been shown to have antimicrobial activity.

Use in DISColi

As previously mentioned, latherin is able to temporality bind to hydrophobic surfaces. It is therefore suspected that latherin may have a disruptive effect on biofilms.

Biobrick:

We have created a biobrick of Latherin. The cDNA which encodes latherin has been cloned and expressed in E.coli. We received the protein in a plasmid from researchers here at The University of Glasgow. It was subsequently amplified by PCR and the biobrick ends were added to it.

Biobrick with 6xHIS tag:

We have also created a version of the Latherin biobrick with a 6xHIS tag (Part:BBa_K660201).

This allows the protein to be isolated using affinity purification.

References & Further Reading:

"Isolation and characterization of latherin, a surface-active protein from horse sweat" which can be accessed here.

"Latherin: A Surfactant Protein of Horse Sweat and Saliva" which can be accessed here

"Latherin Information" by Dr Malcolm Kennedy here

"Biochemical characterization and surfactant properties of horse allergens" which can be accessed here.

"Latherin and other biocompatible surfactant proteins" which can be accessed here