SCIENCE science.org 28 JANUARY 2022 • VOL 375 ISSUE 6579 399PHOTO: RAJA ISLAM/GETTY IMAGES
and posttranslational process-
ing. Melani et al. compiled an
atlas of proteoforms found in 21
cell types in human blood and
bone marrow and show that pro-
teoforms have higher cell-type
specificity than proteins and so
provide better indicators of cell
type. These data are accessible
in the Blood Proteoform Atlas,
and as an example of potential
applications, the authors show
that the proteome signatures
can distinguish normal graft
function from graft rejection in
liver transplants. —VV
Science, aaz5284, this issue p. 411QUANTUM CRITICALITY
Unexpected benefits
of the sign problem
Solving challenging problems
in quantum many-body physics
often involves using numerical
Monte Carlo methods. However,
in the most interesting regime
of strong interactions and low
temperatures, the so-called sign
problem can make calculations
intractable. Mondaini et al.
studied the severity of the sign
problem quantitatively in several
representative models. The
researchers found that quantum
critical behavior in these models
correlated with the regions in the
phase diagram where the sign
problem was most pronounced.
Viewed as a diagnostic for quan-
tum criticality, the sign problem
then becomes a tool (in addition
to being a nuisance). —JS
Science, abg9299, this issue p. 4182D MATERIALS
Control through
spin-orbit coupling
Twisting two graphene layers
with respect to each other by a
small, “magic” angle enhances
electronic correlations in this
two-dimensional (2D) material,
leading to superconductivity and
correlated insulating phases.
These phases can be tuned
by external factors such as
pressure. Lin et al. add another
control knob to this system
by placing a layer of tungsten
diselenide in the proximityEdited by Caroline Ash
and Jesse SmithIN OTHER JOURNALS
VASCULAR DISEASE
Systemic
cardiovascular disease
In the bone marrow, hematopoi-
etic stem cell proliferation and
leukocyte transit are controlled
by the endothelial cells of blood
vessels. Abnormal proliferation
of inflammatory cells is a
hallmark of cardiovascular
disease. However, hypertension,atherosclerosis, and myocardial
infarction, which are prevalent
in cardiovascular disease,
negatively affect the vasculature
systemically. Rohde et al. found
that cardiovascular disease
affected the microvascular
anatomy of the bone marrow
of mice. The authors observed
that the endothelial-derived
cytokine, interleukin (IL)-6,
and an extracellular matrixof the graphene bilayer. This
arrangement results in spin-
orbit coupling at the interface,
causing the appearance of fer-
romagnetism at specific carrier
concentrations. —JS
Science, abh2889, this issue p. 437MOLECULAR BIOLOGY
Dominant association
Intuitively, strong binding
between two biological macro-
molecules means that at any
given time, it is unlikely that
they detach. However, Marklund
et al. show that when the lac
repressor interacts with DNA,
it is primarily the probability of
the repressor recognizing its
target sequence that dictates
the binding strength; the time
spent in the bound conforma-
tion is subordinate. Dissociation
will appear slow because the
molecules can undergo many
rebinding events after leaving
the bound conformation but
before separating in space.
These results shed new light on
the speed-stability paradox of
DNA search kinetics. —DJ
Science, abg7427, this issue p. 442CORONAVIRUS
Reopening without
COVID resurgence
After reopenings in May 2020,
not all US states experienced
a summer COVID resurgence.
Wilke et al. combined 11 streams
of age-structured public health
and mobility data to show that
during these reopenings, mobility
increased but population mixing
remained low, which limited
transmission. This analysis also
revealed that limiting popula-
tion mixing was uneven across
age groups, with the oldest and
most vulnerable having the least
flexibility. These findings illustrate
the potential of multiple clinical
data streams to support more
accurate epidemic transmission
models and explain how certain
states managed their May 2020
reopenings to avoid a resurgence
of COVID transmission later in
the summer. —AJC
S c i. Ad v. 10.1126/
sciadv.abf9868 (2022).Sunflowers rearrange their
carbon metabolism to cope
with drought conditions.PLANT SCIENCEDrought shifts carbon metabolism
P
hotosynthetic cells harness the sun’s power by assimi-
lating carbon through the Calvin-Benson cycle. This
cycle is usually self-sufficient and regenerates its own
substrate, ribulose 1,5-bisphosphate. After analyzing
hydrogen isotopes in sunflower leaf starch, Wieloch
et al. found evidence for an additional substrate supply
with carbon diverted from the oxidative pentose phosphate
pathway. These inputs increased as carbon dioxide concen-
trations inside the leaves decreased, a condition seen under
drought. Rearrangement of carbon metabolism is likely to
affect plant performance and biosphere-atmosphere carbon
dioxide exchange in response to drought. —PJH
New Phytol. 10.1111/nph.17957 (2022).