Reasons to Believe

The Provocative Case for Intelligent Design: New Discovery Highlights Machine-Like Character of the Bacterial Flagellum

Pop music icon and performance artist Lady Gaga goes out of her way to be provocative. Other celebrities are provocative unintentionally.

The same is true about the features of the cell’s chemical systems. As discussed in my book, The Cell’s Design, the defining characteristics of biochemical systems are all indicators of intelligent design. Yet, some of the molecular markers for design are difficult for the uninitiated to appreciate and I find that I have to go out of my way to help people understand why certain chemical systems evince the work of a Creator.

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On the other hand, other characteristics make the case for biochemical intelligent design all by themselves. I only have to describe them and it becomes intuitively obvious to almost everyone that these systems must be the work of a Mind.

One of the most provocative features of the cell’s chemistry is the protein complexes that function as molecular motors. In many instances, these molecular motors bear a startling similarity to man-made machines with respect to their architecture and mode of operation.  (Go here for an article that describes an example recently discovered by biochemists.)

Perhaps the most talked-about molecular machine is the bacterial flagellum. An ensemble of over 40 different kinds of proteins makes up this biochemical celebrity. The proteins function in concert as a literal rotary motor. The flagellum’s components include a rotor, stator, driveshaft, bushing, universal joint, and propeller. Essentially, the bacterial flagellum is a molecular-sized electrical motor directly analogous to man-made rotary motors. The flagellum’s rotation is powered by positively charged hydrogen ions flowing through the bacterial inner membrane.

In recent years, biochemists have discovered even more features of the flagellum that further highlight its machine-like characteristics. (Go here and here for articles on these discoveries.) Recent work by scientists from Australia adds to the list of features by revealing new insight into the flagellum’s switching mechanism.1

The flagellum can spin at high velocities (perhaps as fast as 100,000 rpm under certain conditions) and it can switch the direction of rotation almost instantaneously. In order to understand how this motor can change its rotational direction so abruptly, the scientists determined the atomic-level details of the protein FliG, which contributes to the structure of the flagellum’s rotor. They found that multiple copies of FliG form a ring that plays a role in torque generation. When it’s time to switch the direction of rotation, the FliG proteins undergo a structural change that alters the spatial distribution of electrically charged amino acids within the protein.

This discovery serves to further highlight the machine-like quality of the bacterial flagellum and with it the case for biochemical intelligent design.

The Bacterial Flagellum and the Provocative Case for Intelligent Design

In my book The Cell’s Design, I follow after William Paley, arguing that biochemical systems share many features in common with objects and systems produced by human designers. And because of this parallel we can take such features in natural systems as evidence for intelligent design. In other words, if certain characteristics and features indicate that a structure or process is the product of a human mind and we observe these same properties in biochemical systems, then by analogy it logically follows that life stems from the work of a Mind as well.

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According to Paley’s famous Watchmaker argument for God’s existence, just as a watch requires a watchmaker, so life needs a Creator. In the case of molecular motors, the startling similarity between the flagellum and man-made machinery can be taken as evidence that a divine Mind created life.

For a more detailed discussion on biomolecular motors’ impact on the Watchmaker argument listen to the podcast  I recorded to accompany The Cell’s Design.

Subjects: Biochemical Design

Dr. Fazale Rana

In 1999, I left my position in R&D at a Fortune 500 company to join Reasons to Believe because I felt the most important thing I could do as a scientist is to communicate to skeptics and believers alike the powerful scientific evidence—evidence that is being uncovered day after day—for God’s existence and the reliability of Scripture. Read more about Dr. Fazale Rana

Endnotes:

1. Lawrence K. Lee et al., “Structure of the Torque Ring of the Flagellar Motor and the Molecular Basis for Rotational Switching,” Nature 466 (August 19, 2010