BIOBM 334 - up by amino acids with a negative charge that attract K to the entry way Because two K ions inside the selectivity filter repel each

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
BioBM 334 Friday Section Topic 1: Describe the structural features that account for the selectivity of the K + channel protein for potassium and not sodium. Because structure determines function, it is important to understand how the formation of the channel relates to its role as a selective filter. The four components of the channel include an outer helix, inner helix, pore helix, and a selectivity filter. The selectivity filter is the primary structural feature that is responsible for taking in K + instead of Na + ions. How the potassium ions but not sodium ions were admitted selectively is because the distance between the potassium ion and the oxygen atoms of the amino acids of in the filter region is the same as that between the potassium ion and the oxygen atoms in the water molecules surrounding the potassium ion when it is hydrated in aqueous solution outside the filter. Thus it can slide through the filter unopposed. More simply explained an electrostatic potential in the Potassium Channel set
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: up by amino acids with a negative charge that attract K + to the entry way. Because two K + ions inside the selectivity filter repel each other, this helps overcome the interaction of the K + ions with the oxygen molecules in the channel and allows the K + ions to travel down the channel. Oxygen plays the roles as a stabilizer of the K + ion when it loses its water molecules and enters the selectivity filter. Around the channel water molecules surround the K + , keeping them stable. The sodium ion however, which is smaller than the potassium ion, cannot pass through the channel. In order to prevent sodium from entering, the spatial restrictions prevent the ions to fit between the oxygen atoms in the filter and therefore remain in the water solution. The ability of the channel to strip the BioBM 334 Friday Section potassium ion of its water and allow it to pass at no cost in energy is a kind of selective catalyzed ion transport....
View Full Document

This note was uploaded on 08/03/2010 for the course BIOBM 3340 taught by Professor Blakenship,j. during the Spring '10 term at Cornell University (Engineering School).

Page1 / 2

BIOBM 334 - up by amino acids with a negative charge that attract K to the entry way Because two K ions inside the selectivity filter repel each

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online