which of the following statements best describes the function of dermcidin (2&mk) course hero

How does dermcidin work?

The trick to the function of dermcidin is the arrangement of amino acids in the helix. The helix is amphipathic, which means that the two sides of the helix have different chemical characteristics. One side has many charged amino acids, (shown here in bright red and blue on the right-hand image; two chains are removed to show the inside), and the opposite side is mostly carbon-rich amino acids, shown in white. This is perfect for creating a pore through a membrane: all the carbon-rich amino acids line up outside and interact with the membrane, and all the charged amino acids line the pore and create a perfect tunnel for ions and water to flow through the membrane.

What is dermcidin PDB entry 2ymk?

The structure of dermcidin (PDB entry 2ymk ) shows how the zinc ions assist the creation of a membrane-puncturing pore. The zinc ions bridge negatively-charged amino acids in neighboring chains, stitching the whole complex together. To take a closer look at this interaction, click on the image for an interactive Jmol.

What are the first lines of defense?

One of our first lines of defense is a collection of small peptides, termed antimicrobial peptides, that are secreted from our cells. These peptides are toxic to a broad spectrum of bacteria, binding to their membranes and disrupting their function. For instance, dermcidin is an antimicrobial peptide secreted by sweat glands ...

What are antimicrobial peptides?

Two antimicrobial peptides, with charged atoms in bright blue and red. These small peptides are so effective that they are deployed in many different types of organisms. They come in many shapes and sizes, but they share the amphipathic structure that allows them to pierce through bacterial cell membranes.

How many amino acids are in a peptide?

The active form of the peptide is 47 amino acids long. As seen in the crystal structure (PDB entry 2ymk ), it folds into a long alpha helix, and then six copies of the peptide assemble to form a pore that penetrates the bacterial membrane. This allows ions to flood across the cell membrane, ultimately killing the cell.

What bonds stabilize antimicrobial peptides?

Many antimicrobial peptides are stabilized by disulfide bonds. Try searching for "defensins" to see some examples.

What is LL-37 in PDB?

This helps to protect it from protein-cutting enzymes in the bacterium that would destroy it. On the right is LL-37 (PDB entry 2k6o ), which forms an alpha helix much like dermcidin. Many other examples may be found the PDB archive.