Abstract: Provided are a TEV protease variant, a fusion protein thereof, a preparation method therefor and the use thereof. Provided are a TEV protease variant with unique properties obtained by screening and a fusion protein thereof. The TEV protease variant has a low enzyme cleavage activity during expression in hosts, and preferably has a lower enzyme cleavage activity compared to an S219V variant having an amino acid sequence as shown in SEQ ID NO: 10. The enzyme cleavage site of the TEV protease variant is selected from EXXYXQG/S/H, wherein X is any amino acid residue, and the enzyme cleavage site is preferably selected from SEQ ID NO: 7 and 8. Fusion expression using the TEV protease variant of the present invention and a polypeptide can be used for preparing a polypeptide quickly and efficiently, thereby solving the problems currently present in the process of the recombinant production of a polypeptide.

Abstract: Disclosed are circuit and method for width measurement of digital pulse signals. The circuit comprises: a sample clock, used to drive all registers in the circuit; an edge detection and interrupt control unit, used to detect a rising edge and a falling edge of a pulse signal on an input pin Input to control signal collection; an integer encoding unit comprising a counter and registers and used to measure an integer part ? of the width of a high or low level on the input pin Input with one period 1/f of the sample clock as a reference unit; a signal capture chain, used to sample an output level of each delay cell DLL; a decimal encoding unit, used to find out and record the propagation position of the pulse edge on the signal capture chain; and a calibration control unit, used to perform calibration.

Abstract: A circuit, for generating ultrahigh-precision digital pulse signals comprises: a pulse edge control circuit used for delaying a signal on an input pin and accurately controlling positions of a rising edge and a falling edge of the pulse signal to accurately control the width of pulses and generate ultrahigh-precision pulses; a static calibration circuit used for calculating step size information representing the relationship between a work clock period of a system and a delay of delay cells in the pulse edge control circuit when the system is powered on to work, and storing the step size information, wherein the step size information is the number of delay cells through which the signal is propagated and passes within one system clock period; and a dynamic calibration circuit used for dynamically calculating step size information when a rising edge or a falling edge of each pulse in the input pin arrives.

Abstract: Disclosed are circuit and method for width measurement of digital pulse signals. The circuit comprises: a sample clock, used to drive all registers in the circuit; an edge detection and interrupt control unit, used to detect a rising edge and a falling edge of a pulse signal on an input pin Input to control signal collection; an integer encoding unit comprising a counter and registers and used to measure an integer part ? of the width of a high or low level on the input pin Input with one period 1/f of the sample clock as a reference unit; a signal capture chain, used to sample an output level of each delay cell DLL; a decimal encoding unit, used to find out and record the propagation position of the pulse edge on the signal capture chain; and a calibration control unit, used to perform calibration.

Abstract: A circuit, for generating ultrahigh-precision digital pulse signals, comprises: a pulse edge control circuit used for delaying a signal on an input pin and accurately controlling positions of a rising edge and a falling edge of the pulse signal to accurately control the width of pulses and generate ultrahigh-precision pulses; a static calibration circuit used for calculating step size information representing the relationship between a work clock period of a system and a delay of delay cells in the pulse edge control circuit when the system is powered on to work, and storing the step size information, wherein the step size information is the number of delay cells through which the signal is propagated and passes within one system clock period; and a dynamic calibration circuit used for dynamically calculating step size information when a rising edge or a falling edge of each pulse in the input pin arrives.

Abstract: Provided are a TEV protease variant, a fusion protein thereof, a preparation method therefor and the use thereof. Provided are a TEV protease variant with unique properties obtained by screening and a fusion protein thereof. The TEV protease variant has a low enzyme cleavage activity during expression in hosts, and preferably has a lower enzyme cleavage activity compared to an S219V variant having an amino acid sequence as shown in SEQ ID NO: 10. The enzyme cleavage site of the TEV protease variant is selected from EXXYXQG/S/H, wherein X is any amino acid residue, and the enzyme cleavage site is preferably selected from SEQ ID NO: 7 and 8. Fusion expression using the TEV protease variant of the present invention and a polypeptide can be used for preparing a polypeptide quickly and efficiently, thereby solving the problems currently present in the process of the recombinant production of a polypeptide.

Abstract: The present invention relates to a method for screening a protease variant and the obtained protease variant, and the protease variant has a special performance. The method for screening the protease variant comprises the following steps: (1) constructing a protease random mutation library, optimizing a protease random mutation virus library, and optimizing a protease random mutation phage library; (2) for the protease random mutation library, optimizing the protease random mutation virus library, and optimizing the protease random mutation phage library and screening a protease variant having weak protease enzyme-cutting activity in a host or a similar condition and having protease enzyme-cutting activity in an in vitro denaturation condition; and (3) the step of optionally characterizing the protease variant, wherein the protease optimizes TEV protease or enterokinase. The protease variant in the present invention facilitates industrial production of protein.