Journal of Microbiology

Characteristics of protease inhibitor produced by streptomyces fradiae SMF9: Kim, Hyoung Tae , Suh, Joo Won , Lee, Key Joon; J. Microbiol. 1995;33(2):103-108.

Abstract: Streptomyces fradiae protease inhibitor (SFI) was purified effectively by preparative isoelectric focusing and hydroxyapatite chromatography. The molecular weight of SFI was estimated to be 1.7 kDa by SDS-PAGE and 1.8 kDa by molecular sieving HPLC. One hundred and sixty amino acid residues were determined from which molecular weight of SFI was calculated to be 17.054 Da and carbohydrate residue was not detected. SFI was calculated to be 17,064 Da and carbohydrate residue was not detected. SFI was a monomeric protein with two reactive sits, of which isoelectric point was pH 4.1. N-terminal amino acid sequence of SFI had homology with SSI (Streptomyces subsilisin inhibitor) and other protease inhibitors produced by Streptomyces.

Expression of Human Protease Inhibitor Nexin-I in Escherichia coli: Ha, Sang Deuk , Kim, Ji Ha , Park, Hey Lyoun , Hyun, Hyung Hwan , Chung, Hyung Min , Kim Kwon, Yun Hee , Seo, Seong Yum , Ko, Jung Jae , Lee, Hyun Hwan; J. Microbiol. 1998;36(4):283-288.

Abstract: Human protease inhibitor nexin-I(NX-I) cDNA(1.2Kb) was isolated from human lung cDNA library and expressed under the control of T7 promoter as a fused protein in Escherichia coli BL21 and E. coli GJ1158 by addition of IPTG and Nacl as inducers. For GJ1158, 300 mM NaCl was added for induction after the cell reached A_600=0.6. As a result, E. coli GJ1158 showed higher expression level than BL2l with lesser extent of inclusion bodies. The optimum concentration of NaCl exerting no induction effect but shortening the time to reach A_600=0.6 was 50 mM. All the results suggested that E. coli GJ1158 was a useful host for efficient expression of NX-I using NaCl as an inducer. The expressed NX-1 showed an inhibitory effect on thrombin activity. The expressed protein was purified by immobilized metal affinity column chromatography (IMAC) and characterized by digestion with enterokinase (EK).

A Recombinant Human [alpha]_1-Antitrypsin Variant, M_malton, Undergoes a Spontaneous Conformational Conversion into a Latent Form: Chan-Hun Jung , Hana Im; J. Microbiol. 2003;41(4):335-339.

Abstract: Many genetic variants of [alpha]_1-antitrypsin have been associated with early onset emphysema and liver cirrhosis. However, the detailed structural basis of pathogenic [alpha]_1-antitrypsin molecules is rarely known. Here we found that a recombinant M_malton variant (Phe52-deleted) lost inhibitory activity by spontaneous conformational conversion into a more stable, inactive form under physiological conditions. Biochemical and spectroscopic data suggested that the variant converts into a reactive center loop-inserted conformation, resembling the latent form of plasminogen activator inhibitor-1.

Search