Question

How many tetrapeptides containing alanine, serine, leucine, and glutamic acid do you think there are? Use the three-letter abbreviations to name three.

Short answer

There are 256 tetrapeptides. Three examples are Ala-Ser-Leu-Glu, Ser-Leu-Glu-Ala, and Leu-Glu-Ala-Ser.

Step-by-step solution

Understanding Tetrapeptides

A tetrapeptide is a chain of four amino acids. Each position in the chain can be occupied by any of the given amino acids: alanine (Ala), serine (Ser), leucine (Leu), and glutamic acid (Glu). We need to find the number of different tetrapeptides that can be formed.

Calculating Possible Combinations

Since there are four positions and each position can be filled by any of the four amino acids, we calculate the total number of tetrapeptides as follows: \[ 4 \times 4 \times 4 \times 4 = 4^4 = 256. \] Thus, there are 256 different tetrapeptides possible.

Naming Three Tetrapeptides

Using the three-letter abbreviations, we can name any three tetrapeptides such as: 1. Ala-Ser-Leu-Glu 2. Ser-Leu-Glu-Ala 3. Leu-Glu-Ala-Ser

Key concepts

Amino Acids

Amino acids are the building blocks of proteins. They are organic compounds composed of nitrogen, carbon, hydrogen, and oxygen, along with a side-chain specific to each amino acid.
Amino acids play critical roles in processes like protein synthesis, tissue repair, and nutrient absorption.

• There are 20 standard amino acids that combine in various sequences to form peptides and proteins.
• Each amino acid is represented by a three-letter abbreviation, which is commonly used when naming peptide chains.

In the context of tetrapeptides, which are short chains containing four amino acids, we focus on alanine, serine, glutamic acid, and another amino acid like leucine. The order of these amino acids in the chain determines the type and properties of the tetrapeptide created.
Understanding amino acids and their sequences is essential in fields like biochemistry and genetics, where they influence both structure and function of proteins.

Alanine

Alanine is a non-essential amino acid, meaning our bodies can produce it, so it doesn't need to be obtained through the diet. It is symbolized by 'Ala'.
Alanine plays a vital role in the metabolism of glucose and is an important source of energy for muscles and the central nervous system.

• Alanine helps convert glucose for energy and support our tissues during intensive exercises.
• It is involved in protein synthesis, making it a significant contributor to muscle integrity and development.

In tetrapeptides, alanine can be located at any position, contributing to variations in peptide structure. Its presence can affect the peptide's stability and reactivity, as it is hydrophobic and often resides in protein interiors, away from water.
Familiarity with alanine and its characteristics helps in understanding its role in various biochemical pathways.

Serine

Serine is a polar amino acid, denoted by 'Ser'. It is notable for its role in the catalytic functions of enzymes due to the presence of a reactive hydroxyl group (-OH) in its side chain.
This hydroxyl group allows serine to participate in hydrogen bonding, making it very important in the structure and function of proteins.

• Serine is involved in the synthesis of other amino acids, nucleotides, and fatty acids.
• It contributes to metabolism and the biosynthesis of proteins and phospholipids.

Within tetrapeptides, serine can create sites for bonding and interaction due to its capacity to form hydrogen bonds. Its position can influence the solubility and the functional role of the peptide in cellular processes.
By understanding serine, its interactions, and reactivity, we can appreciate its significance in many biological reactions and protein structures.

Glutamic Acid

Glutamic acid, represented as 'Glu', is an acidic amino acid with a carboxyl group that can donate protons, making it crucial in enzymatic activity and cellular signaling.
It plays a significant role in neurotransmission, particularly as an excitatory neurotransmitter in the central nervous system.

• Glutamic acid is instrumental in cellular metabolism and the urea cycle.
• It is a precursor to the synthesis of gamma-aminobutyric acid (GABA), a key inhibitory neurotransmitter.

In the context of tetrapeptides, glutamic acid's acidic properties help in conferring charge states and influencing interaction with surroundings. This characteristic makes it essential in determining the overall behavior of the peptide.
Recognizing the functions and properties of glutamic acid provides insights into its role in diverse physiological and biochemical processes.