# Imaging Macromolecules with X-ray laser pulses

- Institution: CERN
- Department: CERN Colloquium
- Speaker: Henry Chapman
- Year: 2017
- Language: English
- Source: [CERN](https://videos.cern.ch/record/3006730)
- Licence: [CERN](http://copyright.web.cern.ch)
- Who can watch: Teens profiles and older (sources give no ratings; placed by Invisible Network from the source's own words)

The short wavelength of X-rays allows us to resolve atoms, but in practise for biological materials the achievable resolution is limited by the destruction of the sample by the radiation that forms the image. For over 100 years, the workaround to this problem of radiation damage has been to average signals from repeating copies of the object arranged in a large crystal. It is now possible to overcome damage limits by using intense X-ray pulses that vaporise the sample, but which are short enough in duration to freeze any motion of the sample on the atomic scale. With the advent of X-ray FELs we have been able to confirm this principle, and are now applying it to overcoming a major bottleneck for protein crystallography, which is the need for large well-diffracting crystals. The intense pulses also open up opportunities to help solve the crystallographic phase problem. In particular we have found that commonly-occurring disordered crystals that are usually not considered useful for measurement, can be treated as an ensemble of isolated but aligned molecules. The continuous diffraction from this ensemble can be treated as "single molecule" diffraction, which can be used to directly synthesis an image of the molecule. We demonstrate this technique by reconstructing images of photosystem II complexes at 3.5 Å resolution. .

0:00:00 Slide 1

0:02:52 Slide 2

0:04:11 Slide 3

0:05:07 Slide 4

0:06:05 Slide 5

0:06:40 Slide 6

0:07:11 Slide 7

0:08:29 Slide 8

0:09:01 Slide 9

0:10:45 Slide 10

0:15:06 Slide 11

0:15:52 Slide 12

0:17:02 Slide 13

0:17:28 Slide 14

0:19:29 Slide 15

0:20:25 Slide 16

0:21:06 Slide 17

0:21:25 Slide 18

0:21:31 Slide 19

0:22:05 Slide 20

0:23:15 Slide 21

0:23:43 Slide 22

0:24:19 Slide 23

0:26:07 Slide 24

0:26:35 Slide 25

0:27:06 Slide 26

0:27:29 Slide 27

0:28:01 Slide 28

0:28:10 Slide 29

0:28:17 Slide 30

0:29:09 Slide 31

0:30:00 Slide 32

0:30:24 Slide 33

0:30:30 Slide 34

0:30:40 Slide 35

0:32:46 Slide 36

0:33:31 Slide 37…

## Lectures

1. [Imaging Macromolecules with X-ray laser pulses](https://invisiblenetwork.ai/learn/cern/3006730/b5623213e3cf), 1 h 22 min (CERN's player)