scholarly journals Generation of a Novel High-Affinity Antibody Binding to PCSK9 Catalytic Domain with Slow Dissociation Rate by CDR-Grafting, Alanine Scanning and Saturated Site-Directed Mutagenesis for Favorably Treating Hypercholesterolemia

Biomedicines ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 1783
Author(s):  
Zhengli Bai ◽  
Menglong Xu ◽  
Ying Mei ◽  
Tuo Hu ◽  
Panpan Zhang ◽  
...  
Keyword(s):  
Catalytic Domain ◽  
Dissociation Rate ◽  
Site Directed Mutagenesis ◽  
Directed Mutagenesis ◽  
Molecular Docking Study ◽  
Alanine Scanning Mutagenesis ◽  
Alanine Scanning ◽  
High Affinity ◽  
Cdr Grafting ◽  
Slow Dissociation

Inhibition of proprotein convertase subtilisin/kexin type 9 (PCSK9) has become an attractive therapeutic strategy for lowering low-density lipoprotein cholesterol (LDL-C). In this study, a novel high affinity humanized IgG1 mAb (named h5E12-L230G) targeting the catalytic domain of human PCSK9 (hPCSK9) was generated by using CDR-grafting, alanine-scanning mutagenesis, and saturated site-directed mutagenesis. The heavy-chain constant region of h5E12-L230G was modified to eliminate the cytotoxic effector functions and mitigate the heterogeneity. The biolayer interferometry (BLI) binding assay and molecular docking study revealed that h5E12-L230G binds to the catalytic domain of hPCSK9 with nanomolar affinity (KD = 1.72 nM) and an extremely slow dissociation rate (koff, 4.84 × 10−5 s−1), which interprets its quite low binding energy (−54.97 kcal/mol) with hPCSK9. Additionally, h5E12-L230G elevated the levels of LDLR and enhanced the LDL-C uptake in HepG2 cells, as well as reducing the serum LDL-C and total cholesterol (TC) levels in hyperlipidemic mouse model with high potency comparable to the positive control alirocumab. Our data indicate that h5E12-L230G is a high-affinity anti-PCSK9 antibody candidate with an extremely slow dissociation rate for favorably treating hypercholesterolemia and relevant cardiovascular diseases.

scholarly journals Generation of a Novel High-Affinity Antibody Binding to PCSK9 Catalytic Domain with Slow Dissociation Rate by CDR-Grafting, Alanine Scanning and Saturated Site-Directed Mutagenesis

2021 ◽  
Author(s):  
Zhengli Bai ◽  
Menglong Xu ◽  
Ying Mei ◽  
Tuo Hu ◽  
Panpan Zhang ◽  
...  
Keyword(s):  
Catalytic Domain ◽  
Dissociation Rate ◽  
Antibody Binding ◽  
Site Directed Mutagenesis ◽  
Directed Mutagenesis ◽  
Alanine Scanning Mutagenesis ◽  
Alanine Scanning ◽  
High Affinity ◽  
Cdr Grafting ◽  
Slow Dissociation

Abstract Inhibition of Proprotein convertase subtilisin/kexin type 9 (PCSK9) has become an attractive therapeutic strategy for lowering low-density lipoprotein cholesterol (LDL-C). In this study, a novel high affinity humanized IgG1 mAb (named h5E12-L230G) targeting the catalytic domain of human PCSK9 (hPCSK9) was generated by using CDR-grafting, alanine-scanning mutagenesis, and saturated site-directed mutagenesis. To eliminate the cytotoxic effector functions and mitigate the heterogeneity, the heavy-chain constant region of h5E12-L230G was modified with L234A/L235A/N297G mutations and C-terminal lysine deletion. The biolayer interferometry (BLI) binding assay and molecular docking study revealed that h5E12-L230G binds to the catalytic domain of hPCSK9 with nanomolar affinity (KD =1.72 nM) and an extremely slow dissociation rate (koff, 4.84 × 10−5 s−1), which interprets its quite low binding energy (-54.97 kcal/mol) with hPCSK9. Additionally, h5E12-L230G elevated the levels of LDLR and enhanced the LDL-C uptake in HepG2 cells, as well as reduced the serum LDL-C and total cholesterol (TC) levels in hyperlipidemic mouse model with high potency comparable to Alirocumab. Our data suggest that h5E12-L230G is a highly potent antibody binding to PCSK9 catalytic domain with slow dissociation rate which may be utilized as a therapeutic candidate for treating hypercholesterolemia and relevant cardiovascular diseases.

Probing the Interaction between a High-Affinity Single-Chain Fv and a Pyrimidine (6-4) Pyrimidone Photodimer by Site-Directed Mutagenesis†

Biochemistry ◽  
1999 ◽  
Vol 38 (2) ◽  
pp. 532-539 ◽  
Author(s):  
Hiroyuki Kobayashi ◽  
Hiroshi Morioka ◽  
Kunihiro Tobisawa ◽  
Takuya Torizawa ◽  
Koichi Kato ◽  
...  
Keyword(s):  
Site Directed Mutagenesis ◽  
Directed Mutagenesis ◽  
Single Chain ◽  
High Affinity ◽  
Single Chain Fv

scholarly journals Mapping the BKCa Channel's “Ca2+ Bowl”

2004 ◽  
Vol 123 (5) ◽  
pp. 475-489 ◽  
Author(s):  
Lin Bao ◽  
Christina Kaldany ◽  
Ericka C. Holmstrand ◽  
Daniel H. Cox
Keyword(s):  
Fusion Protein ◽  
Binding Site ◽  
Site Directed Mutagenesis ◽  
Directed Mutagenesis ◽  
Membrane Domain ◽  
Intracellular Domain ◽  
High Affinity ◽  
Acidic Residues ◽  
The Relationship

There is controversy over whether Ca2+ binds to the BKCa channel's intracellular domain or its integral-membrane domain and over whether or not mutations that reduce the channel's Ca2+ sensitivity act at the point of Ca2+ coordination. One region in the intracellular domain that has been implicated in Ca2+ sensing is the “Ca2+ bowl”. This region contains many acidic residues, and large Ca2+-bowl mutations eliminate Ca2+ sensing through what appears to be one type of high-affinity Ca2+-binding site. Here, through site-directed mutagenesis we have mapped the residues in the Ca2+ bowl that are most important for Ca2+ sensing. We find acidic residues, D898 and D900, to be essential, and we find them essential as well for Ca2+ binding to a fusion protein that contains a portion of the BKCa channel's intracellular domain. Thus, much of our data supports the conclusion that Ca2+ binds to the BKCa channel's intracellular domain, and they define the Ca2+ bowl's essential Ca2+-sensing motif. Overall, however, we have found that the relationship between mutations that disrupt Ca2+ sensing and those that disrupt Ca2+ binding is not as strong as we had expected, a result that raises the possibility that, when examined by gel-overlay, the Ca2+ bowl may be in a nonnative conformation.

Interactions between factor XIII and the αC region of fibrinogen

Blood ◽  
2011 ◽  
Vol 117 (12) ◽  
pp. 3460-3468 ◽  
Author(s):  
Kerrie A. Smith ◽  
Penelope J. Adamson ◽  
Richard J. Pease ◽  
Jane M. Brown ◽  
Anthony J. Balmforth ◽  
...  
Keyword(s):  
Surface Plasmon Resonance ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
Factor Xiii ◽  
Site Directed Mutagenesis ◽  
Directed Mutagenesis ◽  
Enhancing Effect ◽  
High Affinity ◽  
A Subunit ◽  
First Time

Abstract Fibrinogen αC residues 242-424 have been shown to have a major regulatory role in the activation of factor XIII-A2B2 (FXIII-A2B2); however, the interactions underpinning this enhancing effect have not been determined. Here, we have characterized the binding of recombinant (r)FXIII-A subunit and FXIII-A2B2 with fibrin(ogen) and fibrin αC residues 233-425. Using recombinant truncations of the fibrin αC region 233-425 and surface plasmon resonance, we found that activated rFXIII-A bound αC 233-425 (Kd of 2.35 ± 0.09μM) which was further localized to αC 389-403. Site-directed mutagenesis of this region highlighted Glu396 as a key residue for binding of activated rFXIII-A. The interaction was specific for activated rFXIII-A and depended on the calcium-induced conformational change known to occur in rFXIII-A during activation. Furthermore, nonactivated FXIII-A2B2, thrombin-cleaved FXIII-A2B2, and activated FXIII-A2B2 each bound fibrin(ogen) and specifically αC region 371-425 with high affinity (Kd < 35nM and Kd < 31nM, respectively), showing for the first time the potential involvement of the αC region in binding to FXIII-A2B2. These results suggest that in addition to fibrinogen γ′ chain binding, the fibrin αC region also provides a platform for the binding of FXIII-A2B2 and FXIII-A subunit.

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