Helices are formed by smooth curves, such as a ribbon wrapped around a stick or a spiral staircase. In biology, large molecules fold into complex shapes, including the helix, which plays a crucial role in determining the molecule’s properties and function. The helix can be right or left-handed, and its orientation is determined by the movement along its length. The alpha helix, a right-handed shape, is crucial for the stability of proteins, including keratin and collagen. DNA and RNA also have an alpha helical structure, which is important for protecting genetic material.
A helix is a shape formed by a smooth curve. To visualize this shape one can imagine a ribbon wrapped around a stick, or the coiled cord between a telephone handset and its base. A spiral staircase is another practical example.
In biology, large molecules don’t exist simply as long, straight chains; instead, they roll up and fold into very complex shapes. The shape of a molecule plays a crucial role in determining the properties and function of the molecule. A helix is one such three-dimensional shape formed by large molecules and has an important role in biology.
The propellers can be right-handed or left-handed, depending on the turn of the curve around the central axis. Orientation can be determined by looking at the module along its length. If the movement away from the viewer is clockwise, then the structure is right-handed. If the movement is counterclockwise, then it is left-handed. Handedness, or chirality, cannot be changed by looking at it from a different perspective, but is an intrinsic property of the form.
In 1951, Linus Pauling and Robert B. Corey of the California Institute of Technology demonstrated that the precise coiling of the keratin protein allowed hydrogen bonds to form and stabilize the structure. What they found was an alpha helix, which is a right-handed shape. They determined that the helical structure helps hold the shape of the molecule and gives it much more stability than when it is uncoiled.
Proteins are made up of chains of amino acids, called polypeptides. Within proteins, each turn of the alpha helix occupies approximately 3.6 amino acids in the chain. The helical shape is maintained through the hydrogen bonds that form between the amino group of an amino acid and the oxygen of the third amino acid beyond it in the chain.
Fibrous proteins, including keratin, exhibit a helical pattern in its most basic form. There are also complex proteins that have helical arrangements, including collagen, which is a triple helix. Collagen consists of three polypeptide chains, each right-handed, all wrapped around each other.
Deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) are two more examples of molecules that have an alpha helical structure. RNA usually consists of a single strand of nucleotides wrapped in an alpha helix, while DNA consists of two strands. It is very rare for DNA to exist in a single strand; instead, two identical chains, oriented in opposite directions, are arranged side by side. The nitrogenous bases between the two connect to each other through hydrogen bonds, forming bridges, like the rungs of a ladder. This makes DNA very stable, which is extremely important for protecting the genetic material stored in a molecule.
Protect your devices with Threat Protection by NordVPN
