02507nas a2200265 4500008004100000022001400041245014900055210006900204260000800273300001100281490000800292520154400300653002901844653003501873653003501908653003901943653002301982653001602005100002002021700002002041700001802061700001602079700002002095856012602115 2022 eng d a1369-703X00aUnderstanding unfolding and refolding of the antibody fragments (Fab). II. Mapping intra and inter-chain disulfide bonds using mass spectrometry0 aUnderstanding unfolding and refolding of the antibody fragments  cMAY a1084390 v1823 a

Disulfide bond formation in recombinant protein therapeutics has a significant impact on the integrity and biological activity of the drug product. Formation of the disulfide linkage is the key rate-limiting step in in vitro refolding and overall manufacturing of the antibody fragments (Fab). This investigation is focused on mapping the intra, and inter-chain disulfide bonds in the in vitro refolded antibody fragments by using mass spectrometry (MS). Biosimilar rHu Ranibizumab and rHu Certolizumab expressed using E. coli were selected for the study. Both Fabs contain ten cysteine residues leading to two intra-chain disulfide bonds on each subunit and a single interchain disulfide linkage. rHu Certolizumab has an additional cysteine which is unpaired and used for pegylation. The amino acid sequence in the disulfide-bonded peptides was confirmed by Collision-induced dissociation (CID), Electron transfer dissociation (ETD) and High-energy collision dissociation (HCD). The light chain (LC) intra-chain disulfide is formed between Cys23-Cys88 and Cys134-Cys194 in both the Fabs. The heavy chain (HC) intra-chain disulfides are formed between Cys22-Cys96 and Cys150-Cys206 in rHu Ranibizumab. LC and HC subunits of rHu Ranibizumab are covalently linked by disulfide linkage formed between Cys214 of LC and Cys226 of HC. This study suggests that information from multiple MS platforms and orthogonal methods for peptide fragmentation can be effectively used to map disulfide linkages in biosimilar therapeutic proteins.

10aAntibody fragments (Fab)10aCollision-induced dissociation10aElectron transfer dissociation10aHigh-energy collision dissociation10ain vitro refolding10aRanibizumab1 aNainwal, Neeraj1 aChirmade, Tejas1 aGani, Kayanat1 aRana, Sunil1 aBhambure, Rahul uhttp://library.ncl.res.in/content/understanding-unfolding-and-refolding-antibody-fragments-fab-ii-mapping-intra-and-inter02731nas a2200241 4500008004100000022001400041245012700055210006900182260000900251300001100260490000800271520191900279653001102198653002002209653002302229653001402252653001602266100001602282700002002298700002202318700002002340856012902360 2023 eng d a0141-813000aChromatography assisted in-vitro refolding and purification of recombinant peptibody: recombinant romiplostim a case study0 aChromatography assisted invitro refolding and purification of re cSEP  a1260370 v2493 a

In-vitro protein refolding is one of the key rate-limiting unit operations in manufacturing of fusion proteins such as peptibodies expressed using E. coli. Dilution-assisted refolding is the most commonly used industrial practice to achieve the soluble, native functional form of the recombinant protein from the inclusion bodies. This study is focused on developing a chromatography-assisted in-vitro refolding platform to produce the biologically active, native form of recombinant peptibody. Recombinant Romiplostim was selected as a model protein for the study. A plug flow tubular reactor was connected in series with capture step affinity chromatography to achieve simultaneous in-vitro refolding and capture step purification of recombinant Romiplostim. Effect of various critical process parameters like fold dilution, temperature, residence time, and Cysteine: DTT ratio was studied using a central composite based design of experiment strategy to achieve a maximum refolding yield of selected peptibody. Under optimum refolding conditions, the maximum refolding yield of 57.0 & PLUSMN; 1.5 % and a purity of over 79.73 & PLUSMN; 3.4 % were achieved at 25-fold dilution, 15 degrees C temperature, 6 h residence time with 6 mM and 10 mM of cysteine and DTT, respectively. The formation of native peptibody structure was examined using various orthogonal analytical tools to study the protein's primary, secondary, and tertiary structure. The amino acid sequence for the disulfide-linked peptide was mapped using collision-induced dissociation (CID) to confirm the formation of interchain disulfide bonds between Cys7-Cys7 and Cys10-Cys10 similarly for intra-chain disulfide bonds between Cys42-Cys102, and Cys148-Cys206. The developed protocol here is a valuable tool to identify high-yield scalable refolding conditions for multi-domain proteins involving inter-domain disulfide bonds.

10aCE-SDS10aDisulfide bonds10aIn-vitro refolding10aPeptibody10aRomiplostim1 aRana, Sunil1 aUghade, Santosh1 aKumthekar, Rupali1 aBhambure, Rahul uhttp://library.ncl.res.in/content/chromatography-assisted-vitro-refolding-and-purification-recombinant-peptibody-recombinant02481nas a2200253 4500008004100000022001400041245012400055210006900179260000800248300001100256490000800267520160400275653002901879653002401908653002701932653002201959653001401981653002301995100002202018700001602040700002002056700002002076856013102096 2023 eng d a1369-703X00aMapping time dependent disulfide bond formation during in-vitro refolding of recombinant peptibody: a Fc-fusion protein0 aMapping time dependent disulfide bond formation during invitro r cAUG a1089690 v1973 a

Disulfide bonds are commonly found in covalent interactions, which play a vital role in establishing the three-dimensional structure of proteins and maintaining their biological activity. This investigation is focused on time dependant mapping of intra and inter-disulfide bonds during in-vitro refolding of recombinant peptibody using LC-ESI-MS/MS. The selected recombinant peptibody is a homodimeric, aglycosylated Fc-fusion protein expressed in E. coli. The amino acid sequence in the disulfide bond containing peptides was confirmed at MS/MS level using the CID-based fragmentation approach. During in-vitro refolding of peptibody, a peptide with inter -chain disulfide bond is observed post 4 h, with low area intensity, and it reached a maximum in 96 h. How-ever, maximum area intensity was reached for the intra-chain disulfide bond in 72 h. Since cysteine residues responsible for intra-chain disulfide bonds are present in complex part of the Fc domain, formation of intra-chain disulfide bonds may be an overall rate-limiting step in recombinant Romiplostim refolding. Proper folding and contributions by non-covalent interactions will be required to form intra-chain disulfide bond. Monitoring time -based formation of such non-covalent interactions was carried out using intrinsic fluorescence during protein refolding. Observations from intrinsic fluorescence show that 4-6 h is most crucial time for domain formation. Observations from this study will help characterize structural integrity and quality during process and product development for consistent product quality.

10aDisulfide bond formation10aIn -vitro refolding10aIntrinsic fluorescence10aMass spectroscopy10aPeptibody10aTime based mapping1 aKumthekar, Rupali1 aRana, Sunil1 aUghade, Santosh1 aBhambure, Rahul uhttp://library.ncl.res.in/content/mapping-time-dependent-disulfide-bond-formation-during-vitro-refolding-recombinant-peptibody