Yan Ning's team Nature issued an article: Research and development of guiding painkillers

The taste of pain is uncomfortable, this is an experience that almost everyone has, and sometimes it hurts really "deadly"
.

Pain, which seems to happen in an instant, actually contains a series of signals
.

On July 7, the latest results of Princeton University professor Yan Ning’s team were published online in Nature
.

This research is the first to analyze the high-definition three-dimensional structure of a human-derived neural tissue N-type voltage-gated calcium ion channel with a resolution of 3.
1 angstroms, providing clues for understanding its function
.

The study also analyzed the structure of the 3.
0 angstrom painkiller Ziconotide (Ziconotide) blocking the channel, providing ideas for the development of specific analgesic drugs for the channel
.

Cut off the pathway and cannot perceive pain

When the needle is pierced into the human body, when the boiling oil splashes on the skin, the nerve endings all over the body are the first to feel.
It will convert the stimulating signal into electrical signals and transmit them to the central nervous system located in the spinal cord.
Electrical signals are converted into chemical signals-neurotransmitters, which are finally transmitted to the brain
.

In the process of transformation from electrical signals to chemical signals, Cav2.
2 is inseparable from the participation of N-type voltage-gated calcium channels in nerve tissue
.

Voltage-gated ion channels are an important class of proteins that control ion transport in cells, including the transport of calcium ions, potassium ions, and sodium ions
.

They play an important role in many physiological processes, such as gene expression, transmission of nerve signals, muscle contraction, nerve degenerative diseases, heart disease, mental illness and so on
.

As an important second messenger in organisms, calcium ions (Ca ²⁺ ) are involved in life processes such as muscle contraction, nerve signal transmission, gland secretion, gene transcription regulation, and cell apoptosis
.

The voltage-gated calcium channel (Cav) protein family includes 10 members.
According to their sequence differences, they can be divided into 3 subfamilies, namely Cav1.
1-1.
4, Cav2.
1-2.
3, Cav3.
1-3.
3
.

In recent years, Yan Ning's team has been committed to the analysis of the three-dimensional structure of different subtypes of Cav.
Previously, it has successfully resolved the structure of Cav1.
1, Cav3.
1 and other complexes
.

In this study, they focused on the family member Cav2.
2
.

Therefore, if Cav2.
2 is artificially cut off, the nerve signals are difficult to conduct, and the brain will not be able to perceive pain
.

Cav2.
2 is shaped like a leaping "horse"

It is not easy to cut off Cav2.
2
.

Currently, there is only one painkiller that relies on blocking Cav2.
2 to function-Ziconotide
.

However, ziconotide can only be administered by intrathecal injection, that is, the drug is directly injected into the subarachnoid space through lumbar puncture, so that the drug is dispersed in the cerebrospinal fluid
.

"From the perspective of structural biology, we want to know what the structure of Cav2.
2 is and how ziconotide binds to it
.

Using single-particle cryo-electron microscopy, the researchers reconstructed the three-dimensional structure of the human Cav2.

The three-dimensional reconstruction image shows that the 3 subunits of Cav2.
2 overlap each other, resembling a "horse" leaping into the air, the "horse head and neck" formed by α2δ-1 stretches out of the cell membrane, and α1 constitutes the "horse body".
"Forefoot" spans the entire transmembrane area, leaving the "hidden legs" β3 kicked in the cell membrane as a support
.

Gao Shuai said, "
Ziconotide is bound at the entrance of calcium ion transport .
Compared with before binding, the outer ring structures of α2δ-1 and α1 move upward in coordination, vacating the position and'giving way' to Qi Kao.
Nopeptide, so that it can bind to proteins
.
"

Provide ideas for the development of pain relief drugs

After in-depth analysis and calculation of its three-dimensional structure, the researchers analyzed the interaction between β3 and α1 subunits
.

"We also found that, unlike Cav1.
1 and Cav3.
1 previously studied, Cav2.
2 has two more structural fragments, CH1 and CH2
.
" Yao Xia said.
At the same time, the four voltage sensors (VSD) of Cav2.
2 are combined.
It does not rise at the same time, where VSD2 presents a "down" conformational state, which has never been observed in the VSD conformations of other family members
.

After further analysis, the researchers also discovered the phospholipid molecule PIP2 in its VSD2, which helps stabilize its "down" conformation
.

"This is very surprising
.
At present, we can't accurately judge the functional state of the entire protein and why it is presented in this way.
This is also a problem
that needs to be studied in the future .
" She said
.

Gao Shuai said, “Our analysis of the structure of Cav2.
2, a representative member of the family, laid the foundation for the future study of the structure and mechanism of Cav channel regulation, and also provided ideas for the design and development of analgesic drugs for Cav2.
2
.
”

Related paper information:

https://doi.
org/10.
1038/s41586-021-03699-6