The amino acids that are negatively charged are Aspartic Acid (Asp) and Glutamic Acid (Glu).
At physiological pH, the side chains of aspartic acid and glutamic acid are nearly always deprotonated, carrying a negative charge. This is why they are often referred to as aspartate (Asp) and glutamate (Glu) in their ionized forms. For instance, aspartic acid is a polar, acidic amino acid described by the formula HOOCCH(NH2)CH2COO−, clearly showing a negative charge on one of its carboxyl groups in its side chain. Their acidic nature and ability to donate a proton result in their characteristic negative charge under typical biological conditions.
Characteristics of Negatively Charged Amino Acids
These amino acids play crucial roles in protein structure and function due to their ionic properties. Their negative charges can:
- Form ionic bonds: Interact with positively charged amino acids (like Lysine, Arginine, Histidine) or metal ions, contributing to the stability of protein structures.
- Participate in catalysis: Act as nucleophiles or bases in enzyme active sites, facilitating chemical reactions.
- Influence protein solubility: The presence of charged residues on the surface of proteins increases their solubility in aqueous environments.
Overview of Negatively Charged Amino Acids
| Full Name | Three-Letter Code | One-Letter Code | Charge at Physiological pH |
|---|---|---|---|
| Aspartic Acid | Asp | D | Negative |
| Glutamic Acid | Glu | E | Negative |
Understanding the charge properties of amino acids is fundamental to comprehending how proteins fold into their three-dimensional structures and perform their diverse biological functions.
