Abstract: A Pyrococcus furiosus Argonaute (PfAgo) mutant protein with mesophilic target nucleic acid cleavage activity and an application thereof are provided. The PfAgo mutant protein has an amino acid mutation on at least one of a 617th position and a 618th position relative to the sequence shown in SEQ ID NO: 1, specifically, K617E/G and/or L618Y/F/W/G. Compared with a wild-type PfAgo protein, the provided PfAgo mutant protein has activity in the temperature range of 30-95 Celsius degree (° C.), effectively expanding application range of prokaryotic Argonaute (pAgo) protein.

Abstract: A middle frame assembly may include a middle frame and a bearing plate, the middle frame may include a frame body having a first surface and a second surface opposite to the first surface, the frame body defines a first through hole penetrating the first surface and the second surface, the bearing plate may include a bearing body having a third surface and a fourth surface opposite to the third surface, and a first extending portion protruding from the third surface and configured to pass through the first through hole and fitting with the frame body, such that the bearing body may be connected to the frame body and that and that the first surface and the third surface may abut against each other.

Abstract: A middle frame may include a middle frame and a bearing plate. The middle frame may include a first surface and a second surface opposite to the first surface and defining a first through hole and a second through hole spaced apart from the first through hole, and both the first through hole and the second through hole may penetrate the first surface and the second surface. The bearing plate may include a bearing body having a third surface, a first extending portion extending from the third surface and configured to pass through the first through hole and have an interference fit with the middle frame, and a second extending portion extending from the third surface, spaced apart from the first extending portion and configured to pass through the second through hole and have a clearance fit with the middle frame.

Abstract: A middle frame assembly may include a middle frame and a bearing plate, the middle frame may include a frame body having a first surface and a second surface opposite to the first surface, the frame body defines a first through hole penetrating the first surface and the second surface, the bearing plate may include a bearing body having a third surface and a fourth surface opposite to the third surface, and a first extending portion protruding from the third surface and configured to pass through the first through hole and fitting with the frame body, such that the bearing body may be connected to the frame body and that and that the first surface and the third surface may abut against each other.

Abstract: A middle frame may include a middle frame and a bearing plate. The middle frame may include a first surface and a second surface opposite to the first surface and defining a first through hole and a second through hole spaced apart from the first through hole, and both the first through hole and the second through hole may penetrate the first surface and the second surface. The bearing plate may include a bearing body having a third surface, a first extending portion extending from the third surface and configured to pass through the first through hole and have an interference fit with the middle frame, and a second extending portion extending from the third surface, spaced apart from the first extending portion and configured to pass through the second through hole and have a clearance fit with the middle frame.