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

세포에서 단백질은 다른 단백질, 핵산 및 소분자 리간드와 같은 다른 분자와 무작위로 충돌합니다.
결합이 비특이적인 경우, 분자 간의 비공유 상호작용은 거의 없이 짧은 연관성을 초래합니다.
특정 리간드가 단백질에 결합하면 상보적인 표면을 따라 광범위한 비공유 상호 작용을 형성합니다. 이러한 복합체는 안정적이며 해리되기 전에 오랫동안 결합 상태를 유지합니다.
결합 상호 작용의 강도는 결합 또는 결합 상수라고도 하는 평형 상수 Kb의 관점에서 보고됩니다. 
Kb는 평형에서 발견되는 결합되지 않은 단백질과 리간드의 농도에 대한 단백질-리간드 복합체의 농도 비율에서 계산할 수 있습니다. 
결합으로 인한 자유 에너지 변화와의 관계를 감안할 때, Kb가 크다는 것은 델타 G의 큰 감소를 의미하며, 이는 단백질과 리간드 사이의 강한 친화력을 나타냅니다.
단백질-리간드 결합에는 두 가지 경쟁 과정이 중요합니다: 단백질과 리간드가 복합체를 형성하기 위한 결합과 복합체를 반응물로 해리하는 것입니다.
협회 불변의 것, k위에, 단백질과 그것의 리간드 사이 초당 의무적인 사건의 수의 측정이다; 그것은 주어진 농도에 단백질에 결합하는 리간드의 비율을 산출하기 위하여 이용될 수 있다. 
반대로, koff는 해리 이벤트의 수를 측정한 것으로, 복합체가 얼마나 빨리 분리되는지를 계산하는 데 사용할 수 있습니다.
결합 속도가 해리 속도와 같을 때 평형에 도달하여 생성물과 반응물의 순 농도가 일정하게 유지됩니다.
따라서 평형 상태에서 k는 단백질과 리간드의 평형 농도의 곱을 곱한 k에 단백질-리간드 복합체의 평형 농도를 곱한 값과 같습니다.
이 표현식을 재배열하면 kon과 koff의 비율이 평형 상태에서 Kb와 같다는 것도 알 수 있습니다.

<ol>
	<li>Pollard, Thomas D. "간단하고 유익한 결합 분석에 대한 가이드." 세포의 분자 생물학 21, no. 23 (2010) : 4061-4067.</li>
	<li>Hulme, Edward C. 및 Mike A. Trevethick. "평형에서의 리간드 결합 분석: 검증 및 해석." 영국 약리학 저널 161, no. 6 (2010): 1219-1237.</li>
	<li>Medina-Franco, José L., Oscar Méndez-Lucio 및 Karina Martinez-Mayorga. "약물 발견을 위한 단백질-리간드 및 단백질-단백질 상호 작용 풍경을 특성화하기 위한 분자 모델링과 화학 정보학 간의 상호 작용." 단백질 화학 및 구조 생물학의 발전, vol. 96, pp. 1-37. 아카데믹 프레스, 2014.</li>
</ol>

평형 결합 상수와 결합 강도

The Equilibrium Binding Constant and Binding Strength

평형 결합 상수(K_b)는 단백질-리간드 상호작용의 강도를 정량화합니다. 반응이 평형 상태에 있을 때 K_b는 다음과 같이 계산할 수 있습니다.

<img alt="Eq1" src="/files/ftp_upload/11513/Equation 1.png" style="text-align: center; width: 650px;" />

여기서 P와 L은 각각 결합되지 않은 단백질과 리간드이고, PL은 단백질-리간드 복합체입니다.

결합된 리간드의 양은 리간드 결합 속도와도 관련이 있으므로 실험에서는 다음 비율을 사용하여 단백질-리간드 결합(k_on) 및 해리(k_off) 속도를 조사하여 K_b를 결정할 수도 있습니다.

<img alt="Eq1" src="/files/ftp_upload/11513/Equation 2.png" style="text-align: center; width: 650px;" />

따라서 평형 결합 상수를 결정하기 위해 결합 분석의 두 가지 범주, 즉 평형 농도를 측정하는 범주와 반응 동역학을 측정하는 범주가 사용됩니다. 이 경우 측정 시 반응이 평형 상태에 있어야 합니다.

평형 농도를 결정하는 방법은 원하는 감도와 신호 감지의 용이성에 따라 달라집니다. 이러한 이유로 분광분석법이 가장 널리 사용됩니다. 이 실험에서 반응은 UV-Vis 분광 광도계로 감지할 수 있는 특정 파장에서 반응물 또는 생성물의 흡광도 변화를 생성합니다. 대안적으로, 반응물 또는 생성물은 형광 프로브로 태그를 붙일 수 있거나 고유 형광단을 함유할 수 있습니다. 그러면, 형광의 변화를 통해 반응 진행을 측정할 수 있습니다. 이러한 분석은 실험의 나머지 부분이 일정하게 유지되는 동안 하나의 반응물의 농도를 변화시켜 수행됩니다. 그런 다음 결과를 그래프로 작성하고 다양한 곡선 맞춤 방법으로 분석할 수 있습니다.

다양한 생화학적 기술과 분광학 기술을 사용하여 단백질과 리간드 사이의 상호작용도 연구됩니다. X선 결정학 및 NMR 분광학을 사용한 구조 분석은 분자 시뮬레이션을 통해 단백질-리간드 상호 작용을 예측하는 데 도움이 됩니다. 단백질-리간드 도킹 연구와 같은 이론적 및 계산적 접근 방식은 약물 후보를 포함한 소분자 리간드의 위치와 상호 작용을 특성화하기 위해 광범위하게 사용됩니다. 컴퓨터를 이용한 약물 설계는 기존의 시행착오 약물 실험 속도를 가속화하기 위한 빠르고 저렴한 대안입니다.

평형 결합 상수(Kb)는 단백질-리간드 상호 작용의 강도를 정량화합니다. Kb는 반응이 ...

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

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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

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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

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How Equilibrium Binding Constant Affects Binding

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