The keratin in hair has a specific and consistent structure across all human hair types.
Basic Structure of Hair Keratin
All 17 human hair keratins share a similar basic molecular structure. The protein is not a uniform chain; instead, it is organized into specific regions. These regions can be categorized as follows:
The Central Rod Domain
- This is the core of the keratin structure.
- It is largely composed of α-helical subsegments which are essentially like tightly coiled springs.
- These α-helical segments are not continuous; instead, they are connected by shorter, more flexible linker regions.
Non-Helical Head and Tail Domains
- Head Domain: Located at the amino terminal of the protein.
- Tail Domain: Found at the carboxyl terminal of the protein.
- Both the head and tail regions are non-helical meaning they lack the coiled structure of the central rod.
- These regions flank the central rod domain.
Summary Table of Hair Keratin Structure
| Domain | Structure | Location | Function |
|---|---|---|---|
| Central Rod Domain | α-helical subsegments with linker regions | Middle | Provides structural strength and flexibility |
| Head Domain | Non-helical | Amino terminal | Involved in protein interactions |
| Tail Domain | Non-helical | Carboxyl terminal | Involved in protein interactions |
Key Points:
- Consistency: All 17 types of human hair keratins adhere to this basic structure.
- Modular Nature: The distinct domains (rod, head, tail) contribute to different properties of the protein.
- α-helices: The coiled nature of the α-helices gives the keratin its strength and elasticity.
- Linker Regions: The presence of linker regions allow for some flexibility within the structure.
In essence, the keratin in your hair is a protein built with a central spring-like core flanked by more flexible ends, creating a structure that is both strong and adaptable.
