Characteristic features in the structure and collagen-binding ability of a thermophilic collagenolytic protease from the thermophile Geobacillus collagenovorans MO-1.
A collagen-degrading thermophile, Geobacillus collagenovorans MO-1, extracellularly produces a collagenolytic protease with a large molecular mass. Complete nucleotide sequencing of this gene after gene cloning revealed that the collagenolytic protease is a member of the subtilisin family of serine proteases and consists of a signal sequence for secretion, a prosequence for maturation, a catalytic region, 14 direct repeats of 20 amino acids at the C terminus, and a region with unknown function intervening between the catalytic region and the numerous repeats. Since the unusual repeats are most likely to be cleaved in the secreted form of the enzyme, the intervening region was investigated to determine whether it participates in collagen binding to facilitate collagen degradation. It was found that the mature collagenolytic protease containing the intervening region at the C terminus bound collagen but not the other insoluble proteins, elastin and keratin. Furthermore, the intervening region fused with glutathione S-transferase showed a collagen-binding ability comparable to that of the mature collagenolytic protease. The collagen-binding ability was finally attributed to two-thirds of the intervening region which is rich in beta-strands and is approximately 35 kDa in molecular mass. In the collagenolytic protease from strain MO-1, hydrogen bonds most likely predominate over the hydrophobic interaction for collagen binding, since a higher concentration of NaCl released collagen from the enzyme surface but a nonionic detergent could not. To the best of our knowledge, this is the first report of a thermophilic collagenolytic protease containing the collagen-binding segment.
Itoi
Yuichi
Y
Department of Applied Biochemistry, Kyoto Prefectural University, Shimogamo, Sakyo, Kyoto 606-8522, Japan.
Horinaka
Mano
M
Tsujimoto
Yoshiyuki
Y
Matsui
Hiroshi
H
Watanabe
Kunihiko
K
D000595:Amino Acid Sequence; D001406:Bacillaceae / Q000201:enzymology*; D001483:Base Sequence; D020134:Catalytic Domain; D003001:Cloning, Molecular; D003094:Collagen / Q000378:metabolism*; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004549:Elastin / Q000378:metabolism; D007633:Keratins / Q000378:metabolism; D008969:Molecular Sequence Data; D008970:Molecular Weight; D011485:Protein Binding; D025941:Protein Interaction Mapping; D021382:Protein Sorting Signals; D020449:Repetitive Sequences, Amino Acid / Q000235:genetics; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D012697:Serine Endopeptidases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*
D004269:DNA, Bacterial; D021382:Protein Sorting Signals; D007633:Keratins; D003094:Collagen; D004549:Elastin; D012697:Serine Endopeptidases