Name: how equilibrium binding constant affects binding
Uploaded: 2023-04-30T18:28:41.000Z
Duration: 2 min 18 s
Channel: JoVE

Hücrede proteinler;diğer proteinler, nükleik asitler gibi diğer moleküllerle ve küçük molekül ligandları ile rastgele çarpışır. Bağlanma spesifik değilse, moleküller arasında az sayıda, kovalent olmayan etkileşim, kısa süreli bir birleşme ile sonuçlanır. Proteine, spesifik bir ligand bağlanırsa, tamamlayıcı yüzeyler boyunca geniş çaplı, kovalent olmayan etkileşimler oluşturur.Bu tip kompleksler kararlıdır ve ayrılmadan önce uzun süre bağlı kalırlar. Bir bağlanma etkileşiminin gücü, bağlanma veya birleşme sabiti olarak da adlandırılan, denge sabiti Kb cinsinden ifade edilir. Kb, denge halinde, protein-ligand kompleksi konsantrasyonunun bağlanmamış protein ve ligand konsantrasyonuna oranından hesaplanabilir.Serbest enerjide bağlanmadan kaynaklanan değişim ile ilişkisi göz önüne alındığında, daha büyük Kb, delta G'de büyük bir azalma anlamına gelir;bu da protein ve ligand arasında güçlü bir afinite olduğunu gösterir. Protein-ligand bağlanması için iki rakip süreç önemlidir:Bir kompleks oluşturmak için bir protein ve bir ligandın birleşmesi ve kompleksin reaktanlara ayrılması. Birleşme sabiti K_on, bir protein ve onun ligandı arasındaki saniye başına gerçekleşen bağlanma olayı sayısının bir ölçüsüdür.Belirli bir konsantrasyonda proteine ligand bağlanma hızını hesaplamak için kullanılabilir. Tersine, K_off, ayrılma olayı sayısının bir ölçüsüdür. Birleşme hızı ayrılma hızına eşit olduğunda ve ürünlerin ve reaktanların konsantrasyonlarının sabit kaldığı denge haline ulaşıldığında, kompleksin ne kadar hızlı parçalandığını hesaplamak için bu değer kullanılabilir.Bu nedenle, denge halinde, K_on çarpı protein ve ligand denge konsantrasyonlarının çarpımı, K_off çarpı protein-ligand kompleksinin denge konsantrasyonuna eşittir. Bu ifade yeniden düzenlendiğinde, denge halinde K_on'un K_off'a oranının Kb'ye eşit olduğunu görürüz.

<ol>
	<li>Pollard, Thomas D. "Basit ve bilgilendirici bağlanma tahlilleri için bir kılavuz." Hücrenin moleküler biyolojisi 21, hayır. 23 (2010): 4061-4067.</li>
	<li>Hulme, Edward C. ve Mike A. Trevethick. "Dengede ligand bağlama deneyleri: doğrulama ve yorumlama." İngiliz farmakoloji dergisi 161, no. 6 (2010): 1219-1237.</li>
	<li>Medina-Franco, José L., Oscar Méndez-Lucio ve Karina Martinez-Mayorga. "İlaç keşfi için protein-ligand ve protein-protein etkileşimlerini karakterize etmek için moleküler modelleme ve kemoinformatik arasındaki etkileşim." Protein kimyası ve yapısal biyolojideki gelişmeler, cilt 96, s. 1-37. Akademik Basın, 2014.</li>
</ol>

denge bağlanma sabiti ve bağlanma kuvveti

The Equilibrium Binding Constant and Binding Strength

Denge bağlanma sabiti (Kb), bir protein-ligand etkileşiminin gücünü ölçer. Reaksiyon dengede olduğunda Kb aşağıdaki şekilde hesaplanabilir:
 <img alt="Eq1" src="/files/ftp_upload/11513/Equation 1.png" style="text-align: center;"> 
 burada P ve L sırasıyla bağlanmamış protein ve liganddır ve PL, protein-ligand kompleksidir.
 Bağlı ligand miktarı aynı zamanda ligand bağlanma hızıyla da ilişkili olduğundan, deneyler ayrıca aşağıdaki oranı kullanarak protein-ligand birleşimi (kon) ve ayrışma (koff) oranlarını inceleyerek Kb'yi belirleyebilir:
<img alt="Eq1" src="/files/ftp_upload/11513/Equation 2.png" style="text-align: center;"> 
 Bu nedenle, denge bağlanma sabitini belirlemek için iki bağlanma tahlili kategorisi kullanılır: denge konsantrasyonlarını ölçenler ve bir reaksiyonun kinetiğini ölçenler. Bu durumda reaksiyonun ölçüm anında dengede olması gerekir.
 Denge konsantrasyonlarını belirleme yöntemi, istenen hassasiyete ve sinyal tespit kolaylığına bağlıdır. Bu nedenlerden dolayı spektroskopik analizler en yaygın şekilde kullanılmaktadır. Bu deneylerde reaksiyon, belirli bir dalga boyunda bir reaktant veya üründe UV-Vis spektrofotometresi tarafından tespit edilebilen bir absorbans (soğurma) değişikliği üretir. Alternatif olarak reaktant veya ürün, bir floresan prob ile etiketlenebilir veya içsel bir florofor içerebilir. Daha sonra reaksiyonun ilerlemesi floresanstaki değişiklikten ölçülebilir. Bu analizler, deneyin geri kalanı sabit tutulurken bir reaktantın konsantrasyonu değiştirilerek gerçekleştirilir. Sonuçlar daha sonra grafik haline getirilebilir ve çeşitli eğri uydurma yöntemleriyle analiz edilebilir.
 Proteinler ve ligandlar arasındaki etkileşimler de çeşitli biyokimyasal ve spektroskopik teknikler kullanılarak incelenmektedir. X-ışını kristalografisi ve NMR spektroskopisini kullanan yapısal analiz, moleküler simülasyonlar yoluyla protein-ligand etkileşimlerinin tahmin edilmesine yardımcı olur. Protein-ligand yanaştırma çalışmaları gibi teorik ve sayısal yaklaşımlar, ilaç adayları da dahil olmak üzere küçük molekül ligandlarının konumunu ve etkileşimlerini karakterize etmek için yaygın olarak kullanılmaktadır. Bilgisayar destekli ilaç tasarımı, geleneksel deneme yanılma ilaç testinin hızını artırmak için hızlı ve düşük maliyetli bir alternatiftir.

Denge Bağlanma Sabiti ve Bağlanma Kuvveti

Denge bağlanma sabiti (Kb), bir protein-ligand etkileşiminin gücünü ölçer. Kb şu şekilde hesaplanabilir: reaksiyon ...

the-equilibrium-binding-constant-and-binding-strength

Education

JoVE Core

Cell Biology

Hücre Biyolojisi

Unit 1

Ünite 1

Energy and Catalysis

Enerji ve Kataliz

KEY TERMS AND CONCEPTS

TEMEL TERİMLER VE KAVRAMLAR

how equilibrium binding constant affects binding

The equilibrium binding constant describes how strongly two molecules bind at equilibrium. It is a useful way to compare binding strength in molecular interactions.

This topic focuses on how binding is measured and what the equilibrium binding constant means. A higher value indicates stronger binding, while a lower value indicates weaker binding. Understanding this constant helps explain how tightly molecules stay together under equilibrium conditions.

The page also connects the binding constant to real binding strength. It shows why this value matters when comparing different molecular pairs. For high school students, it provides a clear link between a chemistry concept and molecular behavior.

How Equilibrium Binding Constant Affects Binding

how-equilibrium-binding-constant-affects-binding

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the equilibrium binding constant and binding strength

The equilibrium binding constant describes how strongly two molecules bind at equilibrium. It is a useful way to compare binding strength in molecular interactions. This topic focuses on how binding is measured and what the equilibrium binding constant means. A higher value indicates stronger binding, while a lower value indicates weaker binding. Understanding this constant helps explain how tightly molecules stay together under equilibrium conditions. The page also connects the binding...

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key terms and concepts

Learn how the equilibrium binding constant reflects binding strength and why higher or lower values matter in molecular interactions at equilibrium.

How Equilibrium Binding Constant Affects Binding | JoVE K12

cell biology

JoVE Core Hücre Biyolojisi, anlaşılması kolay ancak kapsamlı animasyonlu video derslerde karmaşık hücresel süreçleri gösterir. Bu koleksiyon, organeller ve zarlar, hücresel taşıma ve hücre enerjileri dahil olmak üzere hücrelerin temel bileşenlerine ve işlevlerine odaklanır. Gerçek dünya araştırma deneylerinde hücre biyolojisinin uygulanmasını gösteren bilim insanı eylem videoları ile tamamlanmaktadır.

How Equilibrium Binding Constant Affects Binding

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