合成療法與抗生素耐藥性的抵抗

There are currently only a few synthetic agents that bind to and block the widespread membrane transport proteins, ATP-binding cassette transporters (ABC). Scientists at Goethe University and the University of Tokyo identified four of these macrocyclic peptides as models for a novel generation of active substances. They used methods for which the scientists involved are considered world leaders.

目前只有少數(shù)幾種合成劑可以結合并阻斷廣泛的膜轉運蛋白，即ATP結合盒轉運蛋白(ABC)。歌德大學和東京大學的科學家們將其中的四種大環(huán)肽鑒定為新一代活性物質的模型。他們使用了被認為是世界領導者的科學家所采用的方法。

Thanks to deep sequencing, an extremely fast and efficient read-out procedure, the desired macrocyclic peptides could be filtered out of a "library" of macrocyclic peptides comprising trillions of variants (1 with 12 zeroes)—a number that exceeds the number of stars in the Milky Way. The fact that such an enormous amount exists at all is related to a novel procedure: By reprogramming the genetic code, amino acids can be used specifically as active components that are not otherwise used in the cell. In particular, their circular, closed structure distinguishes them from natural proteins.

通過深度測序，極其快速和高效的讀出程序，可以從包含數(shù)萬億個變體(1個帶有12個零)的大環(huán)肽的“庫”中過濾出所需的大環(huán)肽——這個數(shù)字超過了銀河系中的恒星數(shù)量。如此大量的氨基酸存在的事實與一個新穎的過程有關: 通過重新編碼遺傳密碼，氨基酸可以被特別用作細胞中不會被其他方式使用的活性成分。特別是，它們的圓形封閉結構使它們區(qū)別于天然蛋白質。

Credit: Robert Tampé, Institute for Biochemistry, Biocentre, Goethe University Frankfurt

"Because these therapeutics are cyclic, they break down less rapidly in the cell," explains Robert Tampé, Director of the Institute of Biochemistry at Goethe University. "In addition, the ring-shaped active substances are restricted in their spatial structure, so they bind to the target molecule without major rearrangements." A third distinguishing feature makes macrocyclic peptides particularly attractive for scientists: When the active substances are produced, their building instructions are supplied as a "barcode." If certain therapeutics are selected from among a trillion synthetically produced ones, they carry their "name tags" with them, so to speak.

歌德大學生物化學研究所所長羅伯特·坦佩解釋說: “因為這些療法是周期性的，所以它們在細胞中分解的速度較慢。”“此外，環(huán)狀活性物質的空間結構受到限制，因此它們與目標分子結合而不發(fā)生重大的重排。”第三個區(qū)別特征使得大環(huán)肽對科學家特別有吸引力: 當活性物質產(chǎn)生時，它們的構建指令以“條形碼”的形式提供如果某種療法是從一萬億個人工合成的藥物中選出來的，那么可以這么說，它們隨身帶著它們的“名稱標簽”。

So what role do synthetic therapeutics play in antibiotic resistance in bacteria or multidrug resistance in tumor cells? What happens when they encounter the ATP-driven transport molecule that is responsible for resistance by carrying the chemotherapeutic agents out of the cell? In a nutshell, the drugs block the transporter by binding to it. This can happen at the beginning or at the end of a transport process, when the transporter is in a resting state. However, since the scientists can slow down the transport process so that it is carried out in slow motion, they can identify the agents that "enter" in the middle of the transport process and "hold" the membrane protein in its respective position. In this way, the researchers gain an insight into the choreography of the transport process as if through the images of a film strip.

那么，合成療法在細菌的抗生素抗藥性或腫瘤細胞的多藥耐藥性中扮演什么角色呢?當他們遇到 ATP 驅動的轉運分子時會發(fā)生什么? 這種轉運分子通過攜帶化療藥物離開細胞而產(chǎn)生耐藥性?簡而言之，藥物通過與轉運蛋白結合來阻斷轉運蛋白。這可能發(fā)生在運輸過程的開始或結束時，當運輸者處于休眠狀態(tài)。然而，由于科學家們可以減緩運輸過程，使其以慢動作進行，他們可以識別在運輸過程中“進入”的介質，并“保持”膜蛋白在其各自的位置。通過這種方式，研究人員就像通過電影膠片的圖像一樣深入了解了傳輸過程的編排。

These insights have already led to a "paradigm shift" in science, as Tampé explains: "Until now, we have assumed that ATP hydrolysis (an energy-releasing splitting process) provides the energy for transport through the membrane. However, this is only indirectly the case. It is the event of the binding of the ATP molecule that pushes substances out of the cell. The energy of hydrolysis, on the other hand, is used to return the ABC transporter to its initial state." The research groups at Goethe University and the University of Tokyo are convinced that these and other insights into membrane processes will point to the development of future medicines.

這些觀點已經(jīng)導致了科學上的“范式轉變”，正如坦佩解釋的那樣: “直到現(xiàn)在，我們一直假定 ATP 水解(一種能量釋放分裂過程)提供了通過膜傳輸?shù)哪芰?。但是，這僅僅是間接的情況是，ATP分子的結合將物質從細胞中推出。另一方面，水解的能量被用來使 ABC 運輸機恢復到初始狀態(tài)。”歌德大學和東京大學的研究小組確信，這些和其他關于膜過程的觀點將指向未來藥物的發(fā)展。

Basic research on cellular membranes and membrane proteins already has a long tradition in Frankfurt. Robert Tampé elucidated essential mechanisms of ATP-driven transport proteins and cellular machinery of adaptive immune response and quality control, which together with this new publication can provide approaches for applied drug research. Tampé was head of the Collaborative Research Centre "Transport and Communication across Biological Membranes" (SFB 807), which expired at the end of 2020. Meanwhile the concept for a new research center on highly dynamic processes related to protein networks and machineries in cellular membranes is already under development. In the long term, the research results should reveal new possibilities for the therapy of molecular diseases, infections and cancer.

細胞膜和膜蛋白的基礎研究在法蘭克福已經(jīng)有很長的歷史了。羅伯特·坦佩闡明了 ATP 驅動的轉運蛋白和細胞機制的適應性免疫反應和質量控制的基本機制，這一新的出版物可以提供應用藥物研究的方法。坦佩是合作研究中心”跨越生物膜的運輸和通信”(SFB 807)的負責人，該中心于2020年底到期。與此同時，一個關于蛋白質網(wǎng)絡和細胞膜機制高度動態(tài)過程的新研究中心的概念已經(jīng)在發(fā)展之中。從長遠來看，研究結果將為分子疾病、感染和癌癥的治療提供新的可能性。