Rooster other calls as well, and can cluck, similar to the hen. Roosters occasionally make a patterned series of clucks to attract hens to a source of food, the same way a mother hen does for her chicks. Rooster crowing contests are a traditional sport in several countries, such as Germany, the Netherlands, Belgium, the United States, Indonesia and Japan. The oldest contests are held with longcrowers. Depending on the breed, either the duration of the crowing or the times the rooster crows within a certain time is measured. A capon is a castrated rooster. In the caponization procedure, the bird's
S-tag of the S-tag is: Lys-Glu-Thr-Ala-Ala-Ala-Lys-Phe-Glu-Arg-Gln-His-Met-Asp-Ser. It is believed that the peptide with its abundance of charged and polar residues could improve solubility of proteins it is attached to. Moreover, the peptide alone is thought not to fold into a distinct structure. On DNA-level the S-tag can be attached to the N- or C-terminus of any protein. After gene expression, such a tagged protein can be detected by commercially available antibodies. 1. R.T. Raines et al., The S-Tag Fusion System for Protein Purification. Methods Enzymol. 326, 362-367 (2000) S-tag S-tag is the name of an oligopeptide derived from pancreatic ribonuclease A