Cryo-protective effect of an ice-binding protein derived from Antarctic bacteria
Cryo-protective effect of an ice-binding protein derived from Antarctic bacteria
复制标题
DOI：
10.1111/febs.13965
复制
发表时间：
2017-01-01
期刊：
影响因子：
5.4
通讯作者：
Lotti, Marina
中科院分区：
文献类型：
--
作者：
Mangiagalli, Marco;Bar-Dolev, Maya;Lotti, Marina
在寒冷的环境中，生物能够通过各种适应策略来对抗低温的有害影响，包括产生抑制细胞内外冰晶生长的冰结合蛋白（IBPs）。我们描述了这样一种蛋白质（EfcIBP）的特性，该蛋白质是在由纤毛虫focardii Euplotes和嗜冷非培养细菌组成的南极生物联合体的元基因组中鉴定出来的。重组EfcIBP可以抵抗冷冻而没有任何构象破坏，并且具有中等的热稳定性，中点温度为66.4摄氏度。测试了它对冰的影响，EfcIBP显示了其他细菌IBPs中未报道的不寻常的特性组合。首先，它是迄今为止在抑制冰重结晶方面表现最好的IBPs之一，其有效浓度在纳摩尔范围内。此外，EfcIBP具有热滞后活性（50 μ M时0.53℃），当温度保持在热滞后间隙内时，它可以阻止晶体生长。EfcIBP保护纯化的蛋白质和细菌细胞在暴露于具有挑战性的温度下免受冷冻损伤。EfcIBP还具有用于蛋白质运输的潜在n端信号序列和分泌IBPs共有的DUF3494结构域。这些特征使我们假设该蛋白要么锚定在细胞外表面，要么集中在细胞周围，为整个细胞联盟提供生存优势。
Cold environments are populated by organisms able to contravene deleterious effects of low temperature by diverse adaptive strategies, including the production of ice binding proteins (IBPs) that inhibit the growth of ice crystals inside and outside cells. We describe the properties of such a protein (EfcIBP) identified in the metagenome of an Antarctic biological consortium composed of the ciliate Euplotes focardii and psychrophilic non-cultured bacteria. Recombinant EfcIBP can resist freezing without any conformational damage and is moderately heat stable, with a midpoint temperature of 66.4 degrees C. Tested for its effects on ice, EfcIBP shows an unusual combination of properties not reported in other bacterial IBPs. First, it is one of the best-performing IBPs described to date in the inhibition of ice recrystallization, with effective concentrations in the nanomolar range. Moreover, EfcIBP has thermal hysteresis activity (0.53 degrees C at 50 mu M) and it can stop a crystal from growing when held at a constant temperature within the thermal hysteresis gap. EfcIBP protects purified proteins and bacterial cells from freezing damage when exposed to challenging temperatures. EfcIBP also possesses a potential N-terminal signal sequence for protein transport and a DUF3494 domain that is common to secreted IBPs. These features lead us to hypothesize that the protein is either anchored at the outer cell surface or concentrated around cells to provide survival advantage to the whole cell consortium.