Select amino acids play a key role in the entire process

HYDERABAD: How do bacteria without having the mechanism to regulate internal body temperature or technology to alter their surroundings thrive in frozen Antarctica or blistering hot springs?

In a new finding which might have future applications to engineer crops that could grow in varied climates or develop enzymes which perform efficiently at different temperatures, scientists have found that bacterial enzymes remain unaffected by the vagaries of weather, with select amino acids playing a key role in the entire process.

In their experiment, the findings of which were brought out in the advance online publication of "Nature" recently, a team of scientists led by Prof. Avigdor Scherz from the Weizmann Institute of Science, which included P.S. Maruthi Sai from the city, worked with two different types of photosynthetic bacteria (they use sun's energy to create sugars for food). The other team members are -- Oksana Shlyk -Kerner, Ilan Samish, Hadar Kless, David Kaftan and Neta Holland.

Focussing on one of the key stages of photosynthesis, a reaction that takes place in "reaction center" of the bacterial cell, the scientists steadily increased the surrounding temperature to see how increased heat affected the reaction rate. Though they expected the reaction rate to become faster and faster as the temperature rose, the bacterial enzymes defied the rule.


On the contrary, they peaked at a certain temperature after which the rate held steady even as the temperature continued to rise. The peak for each micro-organism occurred right in its optimal "comfort zone". Thus, enzymes remained unaffected by the vagaries of weather but were tuned to work most efficiently at the average temperature of their everyday habitat. This adaptation might protect them from potential ill-effects.