Which of the following proteases will give a clean cut at the N-terminus (i.e. have no additional amino acids present once treated with the protease)?

Question

BlackTom AI · Accepted Answer

To determine which proteases yield a truly seamless N-terminus after cleavage, we must examine the reported cleavage recognition sequences and what residues remain at the new N-terminus post-cleavage.
Option a. TEV: TEV protease recognizes ENLYFQ/G and cleaves between Q and G. This means a Gly (G) residue is left just after the cleavage site, becoming the new N-terminus of the downstream sequence. Therefore, TEV does not provide a completely clean N-terminus with no extra residues. This makes option a incorrect as a universal clean-cut protease for the N-terminus.
Option b. EntK: EntK (Enterokinase) recognizes the DDDDK sequence and cleaves after the lysine (K). The canonical site is DDDDK|X, where X is the next amino acid of the target. Since the cut occurs immediately before X, there are no extra residues appended to the N-terminus of the downstream protein beyond the intended sequence X. This yields a clean N-terminus, making option b a correct choice.
Option c. Xa: Factor Xa recognizes the IEGR sequence and cleaves after R (IEGR|). Similar to EntK, the cut occurs right before the downstream residue, so the N-terminus starts with the intended residue X without additional residues. Hence, Xa yields a clean N-terminus, making option c a correct choice.
Option d. Thr: This option refers to thrombin, which recognizes LVPR|GS and cleaves after R. Cleavage leaves a Gly-Ser (GS) dipeptide at the new N-terminus in many designs, introducing extra residues. Thus thrombin does not provide a completely clean N-terminus. This makes option d incorrect.
Option e. PreScission: PreScission protease recognizes the LEVLFQ/GP site and cleaves between Q and G, often leaving a GP dipeptide at the N-terminus of the downstream product. This results in additional residues at the new N-terminus, so it is not a clean cut. Therefore option e is incorrect.
In summary, the proteases EntK and Xa (Options b and c) are the ones that can give a truly clean N-terminus after cleavage, whereas TEV, Thrombin, and PreScission generally leave extra residues at the N-terminus.

BPS3021 S1 2025 CYL | Protein purification & characterisation

Which of the following proteases will give a clean cut at the N-terminus (i.e. have no additional amino acids present once treated with the protease)?

查看解析

登录即可查看完整答案

类似问题

In a consumer society, many adults channel creativity into buying things

Economic stress and unpredictable times have resulted in a booming industry for self-help products

People born without creativity never can develop it

A product has a selling price of $20, a contribution margin ratio of 40% and fixed cost of $120,000. To make a profit of $30,000. The number of units that must be sold is: Type the number without $ and a comma. Eg: 20000

Which of the following statement regarding cost is correct:

Under the assumptions used in cost-volume-profit analysis, as the activity increases:

The CVP and break-even analysis are supported by a range of important assumptions. Which of the following is not an assumption of the CVP:

The break-even point is that at which:

更多留学生实用工具

考试浏览器助手

风格化写作助手

论文查重助手

文献引用助手

课堂转译助手

课堂笔记助手

Quiz搜索助手

学校历年真题

智能刷题助手

智能匹配练习

希望你的学习变得更简单