Characterization of a New S8 serine Protease from Marine Sedimentary Photobacterium sp. A5–7 and the Function of Its Protease-Associated Domain

Abstract

Bacterial extracellular proteases are important for bacterial nutrition and marine sedimentary organic nitrogen degradation. However, only a few proteases from marine sedimentary bacteria have been characterized. Some subtilases have a protease-associated (PA) domain inserted in the catalytic domain. Although structural analysis and deletion mutation suggests that the PA domain in subtilases is involved in substrate binding, direct evidence to support this function is still absent. Here, a protease, P57, secreted by Photobacterium sp. A5-7 isolated from marine sediment was characterized. P57 could hydrolyze casein, gelatin and collagen. It showed the highest activity at 40°C and pH 8.0. P57 is a new subtilase, with 63% sequence identity to the closest characterized protease. Mature P57 contains a catalytic domain and an inserted PA domain. The recombinant PA domain from P57 was shown to have collagen-binding ability, and Phe349 and Tyr432 were revealed to be key residues for collagen binding in the PA domain. This study first shows direct evidence that the PA domain of a subtilase can bind substrate, which provides a better understanding of the function of the PA domain of subtilases and bacterial extracellular proteases from marine sediment.

Comparative Genomics of Marine Sponge-Derived Streptomyces spp. Isolates SM17 and SM18 With Their Closest Terrestrial Relatives Provides Novel Insights Into Environmental Niche Adaptations and Secondary Metabolite Biosynthesis Potential

“…Protease producing marine bacteria are known to be important in the degradation of organic nitrogen which is essential for nitrogen recycling in marine sediments (Zhang et al, 2015). Marine bacterial proteases are also known to play a role in sponge host nitrogen metabolism, which may also explain the presence of this specific protease in the marine isolates SM17 and SM18, and its absence in their terrestrial counterparts (Li et al, 2016; Kiran et al, 2018). Further work on these specific proteases might also be relevant from an industrial perspective, given the interest in proteases of marine origin which are typically cold adapted, salt tolerant, with broad optimal pH values (Li et al, 2016) and which are particularly suited for a number of biotechnological applications, including laundry detergents, food processing, the leather and textile industries, and in waste water treatment applications (Li et al, 2013; Salwan and Sharma, 2018).…”

A novel oncolytic adenovirus based on simian adenovirus serotype 24

“…This could explain the phenomenon that some types of tumor cells such as A549 and SiHa are insensitive to AdC7-SP/E1A-ΔE3 while other types of tumor cells such as Huh7 and NCI-H508 are sensitive. The antagonism to apoptosis induced by AdC7-SP/E1A-ΔE3 in A549 and SiHa could promote the replication of AdC7-SP/E1A-ΔE3, for cells can limit viral replication through death of the infected cell, which is an important cellular defense mechanism against viral invasion [ 36 ]. However, NCI-H508 and HuH7 cells infected with AdC7-SP/E1A-ΔE3 could be labeled with Annexin V (Figure 4A ), had increasing levels of apoptosis markers (cleaved caspase 3 and PARP) (Figure 4B ), and did not experience declining levels of p62 and increasing levels of LC3 II (Figure 4B ), suggesting that AdC7-SP/E1A-ΔE3 could kill NCI-H508 and Huh7 cell through apoptosis rather than autophagic cell death, for autophagic cell death is accompanied by the declining of p62 and the increases of LC3 II [ 37 ].…”

The basal transcription factor II H subunit Tfb5 is required for stress response and pathogenicity in the tangerine pathotype of Alternaria alternata

“…Multiple protein sequences were aligned by ClustalW program available in MEGA 5.0. The aligned sequences were performed using neighbour‐joining (NJ) analysis in MEGA 5.0 and the tree topology was evaluated with 1,000 bootstrap replicates (Li et al ., 2016).…”