Science - 06.03.2020

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SCIENCE sciencemag.org 6 MARCH 2020 • VOL 367 ISSUE 6482 1087

Edited by Caroline Ash
and Jesse Smith

IN OTHER JOURNALS


ORGANIC CHEMISTRY
Sulfurous glue for
heterocycles
Palladium catalysts can stitch
together a wide variety of carbon-
based aromatic rings, but they
often get hung up if both rings
contain nitrogen. Qin et al. report

that a sulfur reagent can help fill
this gap. Specifically, they show
that isopropyl sulfinyl chloride
can react successively with two
Grignard-activated heterocycles,
such as pyridine rings, and then
couple them together by elimina-
tion. The reaction was compatible
with a wide variety of five- and

PHOTOSYNTHESIS

Bulky lipids for light-harvesting control


L


ipid membranes are extraordinarily complex, with many
different acyl chains, head groups, and proteins contributing
to their shape, curvature, and fluidity. In membranes with
specialized functions, such as the thylakoid membranes
within chloroplasts, these properties can influence the func-
tion of the embedded membrane proteins. Tietz et al. measured
changes in the behavior of proteoliposome-reconstituted light-
harvesting complex II, a protein that normally gathers light for
photosystem II, in the presence or absence of the non–bilayer-
forming lipid monogalactosyldiacylglycerol. In this assay, the
lipid stimulated energy quenching, which would divert light
energy into heat and be photoprotective in high-intensity light.
The authors suggest that changes in lateral membrane pressure
caused by the bulky lipids may influence pigment conformations
within the protein and thus alter the amount of light energy mov-
ing through the system. —MAF
J. Biol. Chem. 295 , 1857 (2020).

Behavioral patterns in fruit f ies, Drosophila melanogaster, vary by individual.

Model of the light-harvesting complex II trimer structure for membranes
containing only bilayer-forming lipids

Key to generating individual
diversity in the population is
the inherent chaos of normal
development. A set of neurons
in the visual system is wired up
in a variable manner, result-
ing in brain circuit asymmetry
unique to each fly that guides
its line-walking behavior. With
more asymmetry in its brain
circuit, a fly is better able to
orient to the line. —PJH
Science, this issue p. 1112

NEUROSCIENCE
Human brain activity
during memory
Animal studies suggest that
sequence replay of neuronal
activity may underlie memory
retrieval and consolidation.
However, there is no direct
evidence that the replay of
spiking activity sequences is
important for these processes
in the human brain. Vaz et
al. simultaneously recorded
single-unit spikes, local field
potential, and intracranial
electroencephalography
signals in the brain while
participants performed a
memory task. Sharp wave
ripple oscillations in the
temporal lobe cortex reflected
bursts of neural spiking,
and these bursts of spikes
organized into sequences
during memory formation.
These sequences were
replayed during successful
memory retrieval. The extent
of sequence replay during cor-
rect recall was related to the
extent to which cortical spik-
ing activity was coupled with
ripples in the medial temporal
lobe. —PRS
Science, this issue p. 1131

PHOTO: NG IMAGES/ALAMY STOCK PHOTO


5-ethynyl-uridine (EU) in single
cells (scEU-seq), which allows
estimation of RNA transcrip-
tion and degradation rates.
When examining intestinal
organoid cells, scEU-seq data
can be used to discern between
transcription and degradation
during development, indicat-
ing that this method can be
applied to better understand
the relationship between gene
expression and RNA degrada-
tion during development. —LMZ
Science, this issue p. 1151

CELL SURFACE MAPPING
Pinpointing proteins
To develop drugs that target a
specific cell surface protein, it’s
helpful to know which other pro-
teins reside in its vicinity. Geri et
al. report a light-triggered label-
ing technique that improves the
spatial resolution for this type of
mapping. Specifically, they rely
on a photocatalyst with a very
short energy-transfer range to
activate a carbene-based label
that can only diffuse a short dis-
tance in water before reacting.
They showcase the technique by
mapping the environment of the
programmed-death ligand 1 (PD-
L1) protein on B cell surfaces, a
system of considerable interest
in cancer immunotherapy. —JSY
Science, this issue p. 1091

NEURODEVELOPMENT
Diversity from
development
When given a line to follow, some
fruit flies do so carefully and
others weave. Linneweber et al.
now show that these behaviors
are stable for an individual but
diverse in an isogenic population.

Published by AAAS
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