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The winding code in proteins: Why is the helical structure so mysterious and important?
In the world of proteins, helical structures exist like a secret language. These structures, called coiled-coils, are multiple alpha helices wound together like ropes and play an essential role in various biological processes. According to research, about 5% to 10% of proteins have this structure, making the coiled coil one of the most common protein-protein interaction motifs.
These proteins play multiple roles in cells, including regulation of gene expression, membrane fusion, and coordinating the function of cellular structures.
History of the discovery of the spiral structure
The possibility of a helical structure was first proposed in 1952, when scientists Linus Pauling and Francis Crick had an in-depth discussion at a meeting in the UK. Since there has been controversy in the scientific community about the spiral structure, the two scientists finally jointly confirmed the existence of this structure. Pauling subsequently submitted a detailed manuscript, and Crick submitted a shorter memorandum a few days later. However, the final conclusion was that the idea was independently proposed by two scientists and there was no intellectual theft.
Francis Crick first proposed the "helical structure" and its mathematical method in his research, laying the foundation for subsequent protein research.
Molecular structure and composition
The coiled-coil structure usually contains a pattern called a "heptad repeat", in which the amino acid residues contained in it are repeated in the pattern of hxxhcxc. The configuration of these amino acids endows the coiled-wire structure with its unique folding ability, enabling it to assemble efficiently in an aqueous environment. When these α-helices are intertwined, the unique distribution of hydrophobic and hydrophilic amino acids provides the thermodynamic driving force that makes this structure stable and functional.
The role of helical structures in biology
The coiled-coil structure is a common feature in many protein families. The main function of these structures is to facilitate interactions between proteins, allowing them to bind tightly to each other. This property is crucial in multiple biological processes, including membrane fusion and intermolecular plasticity.
Key role in membrane fusion
For example, during HIV infection, the viral gp120 glycoprotein binds to the CD4 receptor and the core receptor, thereby promoting the fusion of gp41. The helical repeat sequences in the gp41 structure enable cross-linking between the viral and host cell membranes, thereby initiating the process of membrane fusion.
The structure and function of gp41 are particularly dependent on the formation of a helical structure, which allows the virus to enter the cell smoothly.
As molecular spacer
The winding structure can also be used as a spacer in the cell. The existence of this structure can prevent accidental interactions between protein blocks and effectively separate different cell organelles. Controls intracellular transport.As an aggregation tag
Due to their unique interactions, the helical structure can also be used as a "tag" to stabilize or achieve a specific aggregation state. These features make these proteins particularly important in the study of synthetic nanostructures.
Design and application prospects
In recent years, scientists have made remarkable achievements in designing protein structures that can self-assemble. By utilizing the characteristics of the helical structure, researchers can predict the final protein folding structure based on a specific amino acid sequence, thereby advancing the development of nanostructures.
Such research could change the future of biomedicine, for example in precision drug delivery, regenerative medicine and protein origami.
Future Challenges and Thoughts
Although the research prospects of helical structures are quite broad, the resulting stability issues remain the main challenges to be overcome in the future. Using these structures to create innovative nanomaterials and even create three-dimensional structures in cell culture has become a research hotspot at this stage.
The winding structure brings new understanding and challenges to the basic components of life. How will future research reveal more of its potential functions?
